[browser][wbt] Fix InvalidOperationException: There is no currently active test (#105561)

* Unsubscribe from event handlers
* Fix wasi default scenario

Author: mkhamoyan

eng/pipelines/extra-platforms/runtime-extra-platforms-wasm.yml

@@ -185,7 +185,7 @@ jobs:
       shouldContinueOnError: ${{ not(parameters.isWasmOnlyBuild) }}
       alwaysRun: ${{ variables.isRollingBuild }}
       scenarios:
-        - WasmTestOnV8
+        - WasmTestOnWasmtime
 
   # Hybrid Globalization tests
   - template: /eng/pipelines/common/templates/wasm-library-tests.yml

src/mono/wasm/Wasm.Build.Tests/Common/ToolCommand.cs

@@ -107,7 +107,7 @@ private async Task<CommandResult> ExecuteAsyncInternal(string executable, string
         {
             var output = new List<string>();
             CurrentProcess = CreateProcess(executable, args);
-            CurrentProcess.ErrorDataReceived += (s, e) =>
+            DataReceivedEventHandler errorHandler = (s, e) =>
             {
                 if (e.Data == null)
                     return;
@@ -118,7 +118,7 @@ private async Task<CommandResult> ExecuteAsyncInternal(string executable, string
                 ErrorDataReceived?.Invoke(s, e);
             };
 
-            CurrentProcess.OutputDataReceived += (s, e) =>
+            DataReceivedEventHandler outputHandler = (s, e) =>
             {
                 if (e.Data == null)
                     return;
@@ -129,11 +129,17 @@ private async Task<CommandResult> ExecuteAsyncInternal(string executable, string
                 OutputDataReceived?.Invoke(s, e);
             };
 
+            CurrentProcess.ErrorDataReceived += errorHandler;
+            CurrentProcess.OutputDataReceived += outputHandler;
+
             var completionTask = CurrentProcess.StartAndWaitForExitAsync();
             CurrentProcess.BeginOutputReadLine();
             CurrentProcess.BeginErrorReadLine();
             await completionTask;
 
+            CurrentProcess.ErrorDataReceived -= errorHandler;
+            CurrentProcess.OutputDataReceived -= outputHandler;
+
             RemoveNullTerminator(output);
 
             return new CommandResult(