new task ForceMSBuildGC

Author: pavelsavara

eng/testing/tests.browser.targets

@@ -207,6 +207,8 @@
     </ItemGroup>
 
     <WriteLinesToFile File="$(WasmMainHtmlPath)" Lines="&lt;html&gt;&lt;body&gt;&lt;script type='module' src='$(WasmMainJSFileName)'&gt;&lt;/script&gt;&lt;/body&gt;&lt;/html&gt;" Overwrite="True" Condition="!Exists('$(WasmMainHtmlPath)')"/>
+
+    <ForceMSBuildGC />
   </Target>
 
   <Target Name="_PrepareForAOTOnHelix">

eng/testing/tests.wasi.targets

@@ -129,6 +129,8 @@
               TargetPath="%(WasmFilesToIncludeFromPublishDir.Identity)"
               Condition="'%(WasmFilesToIncludeFromPublishDir.Identity)' != ''" />
     </ItemGroup>
+
+    <ForceMSBuildGC />
   </Target>
 
   <Target Name="_PrepareForAOTOnHelix">

eng/testing/tests.wasm.targets

@@ -93,6 +93,8 @@
              TaskName="Microsoft.WebAssembly.Build.Tasks.GenerateAOTProps"
              AssemblyFile="$(WasmBuildTasksAssemblyPath)" TaskFactory="TaskHostFactory" />
 
+  <UsingTask TaskName="Microsoft.WebAssembly.Build.Tasks.ForceMSBuildGC" AssemblyFile="$(WasmBuildTasksAssemblyPath)" />
+
   <Target Name="_BundleAOTTestWasmAppForHelix" DependsOnTargets="$(_BundleAOTTestWasmAppForHelixDependsOn)">
     <PropertyGroup>
       <_MainAssemblyPath Condition="'%(WasmAssembliesToBundle.FileName)' == $(AssemblyName) and '%(WasmAssembliesToBundle.Extension)' == '.dll'">%(WasmAssembliesToBundle.Identity)</_MainAssemblyPath>

src/tasks/WasmBuildTasks/ForceMSBuildGC.cs

@@ -0,0 +1,19 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using Microsoft.Build.Framework;
+using Microsoft.Build.Utilities;
+
+namespace Microsoft.WebAssembly.Build.Tasks
+{
+    public class ForceMSBuildGC : Task
+    {
+        public override bool Execute()
+        {
+            GC.Collect();
+            GC.WaitForPendingFinalizers();
+            return true;
+        }
+    }
+}