[MT][browser] Disabling tests failing in the last two weeks on MT. (#94051)

* Disabling tests failing in the last two weeks on MT.

* Failures from #93466 should not apply.

* Remove duplicate + other issues connnected to test PR runs.

* Cleanup

* Increasing num of threads instead of disabling.

* Update System.Threading.ThreadPool.Tests.csproj

16 was too low, still failing

* Update System.Threading.ThreadPool.Tests.csproj

32 was failing

Author: ilonatommy

src/libraries/System.ComponentModel.EventBasedAsync/tests/BackgroundWorkerTests.cs

@@ -91,6 +91,7 @@ public async Task RunWorkerAsync_NoOnWorkHandler_SetsResultToNull()
 
         private ManualResetEventSlim manualResetEvent3;
 
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/94050", typeof(PlatformDetection), nameof(PlatformDetection.IsWasmThreadingSupported))]
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
         public void TestCancelAsync()
         {

src/libraries/System.Threading.ThreadPool/tests/System.Threading.ThreadPool.Tests.csproj

@@ -3,6 +3,7 @@
     <IncludeRemoteExecutor>true</IncludeRemoteExecutor>
     <TargetFramework>$(NetCoreAppCurrent)</TargetFramework>
     <TestRuntime>true</TestRuntime>
+    <_WasmPThreadPoolSize Condition="'$(MonoWasmBuildVariant)' == 'multithread'">64</_WasmPThreadPoolSize>
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="ThreadPoolTests.cs" />