[core] use StringComparison.Ordinal everywhere (#4988)

Context: https://docs.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1307
Context: https://docs.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1309
Context: dotnet/runtime#43956

I was reviewing `dotnet trace` output of the .NET Podcast app:

    6.32ms Microsoft.Maui.Controls!Microsoft.Maui.Controls.ShellNavigationManager.GetNavigationState
    3.82ms Microsoft.Maui.Controls!Microsoft.Maui.Controls.ShellUriHandler.FormatUri

The bulk of this time is spent in `string.StartsWith()`, doing a
culture-aware string comparison?

    3.82ms System.Private.CoreLib!System.String.StartsWith
    2.57ms System.Private.CoreLib!System.Globalization.CultureInfo.get_CurrentCulture

This looks to be showing the cost of the 1st culture-aware comparision
plus any time making these slower string comparisons. It would be
ideal if project templates did not even hit
`CultureInfo.get_CurrentCulture`.

To solve this, let's add to the `.editorconfig` file:

    dotnet_diagnostic.CA1307.severity = error
    dotnet_diagnostic.CA1309.severity = error

And then fix all the places errors appear.

There are some complications in projects that use `netstandard2.0`:

1. For `Contains()` use `IndexOf()` instead.

2. Use `#if NETSTANDARD2_0` for `GetHashCode()` or `Replace()`. Use the `char` overload
of `string.Replace()` where possible.

3. Generally, `InvariantCulture` should not be used.

After these changes, the `FormatUri` method disappears completely from
the trace, and we instead get:

    2.88ms Microsoft.Maui.Controls!Microsoft.Maui.Controls.ShellNavigationManager.GetNavigationState

I suspect this saves ~3.44ms for any MAUI app startup, and a small
amount more depending on the number of string comparisions happening.

Author: jonathanpeppers

.editorconfig

@@ -23,6 +23,10 @@ indent_style = tab
 # https://docs.microsoft.com/en-us/dotnet/fundamentals/code-analysis/quality-rules/ca1416
 dotnet_diagnostic.CA1416.severity = none
 
+# Code analyzers
+dotnet_diagnostic.CA1307.severity = error
+dotnet_diagnostic.CA1309.severity = error
+
 # Modifier preferences
 dotnet_style_require_accessibility_modifiers = never:suggestion
 

src/BlazorWebView/src/Maui/Windows/WinUIWebViewManager.cs

@@ -91,7 +91,7 @@ protected override async Task HandleWebResourceRequest(CoreWebView2WebResourceRe
 					{
 						relativePath = _hostPageRelativePath;
 					}
-					relativePath = Path.Combine(_contentRootDir, relativePath.Replace("/", "\\"));
+					relativePath = Path.Combine(_contentRootDir, relativePath.Replace('/', '\\'));
 
 					var winUIItem = await Package.Current.InstalledLocation.TryGetItemAsync(relativePath);
 					if (winUIItem != null)

src/BlazorWebView/src/SharedSource/QueryStringHelper.cs

@@ -3,6 +3,8 @@
 
 #nullable enable
 
+using System;
+
 namespace Microsoft.AspNetCore.Components.WebView
 {
 	internal static class QueryStringHelper
@@ -13,7 +15,7 @@ public static string RemovePossibleQueryString(string? url)
 			{
 				return string.Empty;
 			}
-			var indexOfQueryString = url.IndexOf('?');
+			var indexOfQueryString = url.IndexOf('?', StringComparison.Ordinal);
 			return (indexOfQueryString == -1)
 				? url
 				: url.Substring(0, indexOfQueryString);

src/Compatibility/ControlGallery/src/Android/TestCloudService.cs

@@ -1,3 +1,4 @@
+using System;
 using Microsoft.Maui.Controls.Compatibility.ControlGallery;
 
 namespace Microsoft.Maui.Controls.Compatibility.ControlGallery.Android
@@ -8,7 +9,7 @@ public bool IsOnTestCloud()
 		{
 			var isInTestCloud = System.Environment.GetEnvironmentVariable("XAMARIN_TEST_CLOUD");
 
-			return isInTestCloud != null && isInTestCloud.Equals("1");
+			return isInTestCloud != null && isInTestCloud.Equals("1", StringComparison.Ordinal);
 		}
 
 		public string GetTestCloudDeviceName()

src/Compatibility/ControlGallery/src/Core/GalleryPages/CollectionViewGalleries/DemoFilteredItemSource.cs

@@ -40,7 +40,7 @@ public DemoFilteredItemSource(int count = 50, Func<string, CollectionViewGallery
 		private bool ItemMatches(string filter, CollectionViewGalleryTestItem item)
 		{
 			filter = filter ?? "";
-			return item.Caption.ToLower().Contains(filter?.ToLower());
+			return item.Caption.IndexOf(filter, StringComparison.OrdinalIgnoreCase) != -1;
 		}
 
 		public void FilterItems(string filter)

src/Compatibility/ControlGallery/src/UITests.Shared/Utilities/ParsingUtils.cs

@@ -15,7 +15,7 @@ public static Font ParseUIFont(string font)
 
 			// Logger.LogLine ("TEST PARSING");
 
-			if (font.Contains("font-weight: bold;"))
+			if (font.IndexOf("font-weight: bold;", StringComparison.Ordinal) != -1)
 			{
 				// Logger.LogLine ("Found Bold");
 				fontAttrs = FontAttributes.Bold;

src/Compatibility/ControlGallery/src/WinUI/WinUIStartup.cs

@@ -26,7 +26,7 @@ public static MauiApp CreateMauiApp()
 				.AddWindows(windows => windows
 					.OnLaunching((_, e) =>
 					{
-						if (!string.IsNullOrWhiteSpace(e.Arguments) && e.Arguments.Contains("RunningAsUITests"))
+						if (!string.IsNullOrWhiteSpace(e.Arguments) && e.Arguments.Contains("RunningAsUITests", StringComparison.Ordinal))
 						{
 							App.RunningAsUITests = true;
 							ControlGallery.App.PreloadTestCasesIssuesList = false;

src/Compatibility/ControlGallery/src/iOS/AppDelegate.cs

@@ -89,7 +89,7 @@ public bool IsOnTestCloud()
 		{
 			var isInTestCloud = Environment.GetEnvironmentVariable("XAMARIN_TEST_CLOUD");
 
-			return isInTestCloud != null && isInTestCloud.Equals("1");
+			return isInTestCloud != null && isInTestCloud.Equals("1", StringComparison.Ordinal);
 		}
 
 		public string GetTestCloudDeviceName()

src/Compatibility/Core/src/Android/BorderBackgroundManager.cs

@@ -219,17 +219,17 @@ void BorderElementPropertyChanged(object sender, PropertyChangedEventArgs e)
 				return;
 			}
 
-			if (e.PropertyName.Equals(Button.BorderColorProperty.PropertyName) ||
-				e.PropertyName.Equals(Button.BorderWidthProperty.PropertyName) ||
-				e.PropertyName.Equals(Button.CornerRadiusProperty.PropertyName) ||
-				e.PropertyName.Equals(VisualElement.BackgroundColorProperty.PropertyName) ||
-				e.PropertyName.Equals(VisualElement.BackgroundProperty.PropertyName) ||
-				e.PropertyName.Equals(Specifics.Button.UseDefaultPaddingProperty.PropertyName) ||
-				e.PropertyName.Equals(Specifics.Button.UseDefaultShadowProperty.PropertyName) ||
-				e.PropertyName.Equals(Specifics.ImageButton.IsShadowEnabledProperty.PropertyName) ||
-				e.PropertyName.Equals(Specifics.ImageButton.ShadowColorProperty.PropertyName) ||
-				e.PropertyName.Equals(Specifics.ImageButton.ShadowOffsetProperty.PropertyName) ||
-				e.PropertyName.Equals(Specifics.ImageButton.ShadowRadiusProperty.PropertyName))
+			if (e.PropertyName.Equals(Button.BorderColorProperty.PropertyName, StringComparison.Ordinal) ||
+				e.PropertyName.Equals(Button.BorderWidthProperty.PropertyName, StringComparison.Ordinal) ||
+				e.PropertyName.Equals(Button.CornerRadiusProperty.PropertyName, StringComparison.Ordinal) ||
+				e.PropertyName.Equals(VisualElement.BackgroundColorProperty.PropertyName, StringComparison.Ordinal) ||
+				e.PropertyName.Equals(VisualElement.BackgroundProperty.PropertyName, StringComparison.Ordinal) ||
+				e.PropertyName.Equals(Specifics.Button.UseDefaultPaddingProperty.PropertyName, StringComparison.Ordinal) ||
+				e.PropertyName.Equals(Specifics.Button.UseDefaultShadowProperty.PropertyName, StringComparison.Ordinal) ||
+				e.PropertyName.Equals(Specifics.ImageButton.IsShadowEnabledProperty.PropertyName, StringComparison.Ordinal) ||
+				e.PropertyName.Equals(Specifics.ImageButton.ShadowColorProperty.PropertyName, StringComparison.Ordinal) ||
+				e.PropertyName.Equals(Specifics.ImageButton.ShadowOffsetProperty.PropertyName, StringComparison.Ordinal) ||
+				e.PropertyName.Equals(Specifics.ImageButton.ShadowRadiusProperty.PropertyName, StringComparison.Ordinal))
 			{
 				Reset();
 				UpdateDrawable();

src/Compatibility/Core/src/Android/Renderers/DatePickerRenderer.cs

@@ -160,7 +160,7 @@ void SetDate(DateTime date)
 			{
 				EditText.Text = date.ToShortDateString();
 			}
-			else if (Element.Format.Contains('/'))
+			else if (Element.Format.Contains('/', StringComparison.Ordinal))
 			{
 				EditText.Text = date.ToString(Element.Format, CultureInfo.InvariantCulture);
 			}