Always zero-init if object contains pointers (dotnet#100265)

Author: VSadov

src/coreclr/nativeaot/Runtime/gcrhenv.cpp

@@ -129,6 +129,12 @@ Object* GcAllocInternal(MethodTable *pEEType, uint32_t uFlags, uintptr_t numElem
     ASSERT(!pThread->IsDoNotTriggerGcSet());
     ASSERT(pThread->IsCurrentThreadInCooperativeMode());
 
+    if (pEEType->ContainsPointers())
+    {
+        uFlags |= GC_ALLOC_CONTAINS_REF;
+        uFlags &= ~GC_ALLOC_ZEROING_OPTIONAL;
+    }
+
     size_t cbSize = pEEType->get_BaseSize();
 
     if (pEEType->HasComponentSize())

src/libraries/System.Runtime/tests/System/GCTests.cs

@@ -1100,6 +1100,8 @@ private unsafe static void AllocateArrayPinned_ManagedValueType_CanRoundtripThro
             byte* pointer = (byte*)Unsafe.AsPointer(ref array[0]);
             var size = Unsafe.SizeOf<EmbeddedValueType<string>>();
 
+            GC.Collect();
+
             for(int i = 0; i < length; ++i)
             {
                 int idx = rng.Next(length);