disable parallel runs for MsQuic test (#57190)

Author: wfurt

src/libraries/System.Net.Quic/tests/FunctionalTests/MsQuicTests.cs

@@ -19,6 +19,7 @@
 namespace System.Net.Quic.Tests
 {
     [ConditionalClass(typeof(QuicTestBase<MsQuicProviderFactory>), nameof(IsSupported))]
+    [Collection("NoParallelTests")]
     public class MsQuicTests : QuicTestBase<MsQuicProviderFactory>
     {
         private static ReadOnlyMemory<byte> s_data = Encoding.UTF8.GetBytes("Hello world!");

src/libraries/System.Net.Quic/tests/FunctionalTests/QuicStreamConnectedStreamConformanceTests.cs

@@ -21,6 +21,7 @@ public sealed class MockQuicStreamConformanceTests : QuicStreamConformanceTests
     }
 
     [ConditionalClass(typeof(QuicTestBase<MsQuicProviderFactory>), nameof(QuicTestBase<MsQuicProviderFactory>.IsSupported))]
+    [Collection("NoParallelTests")]
     public sealed class MsQuicQuicStreamConformanceTests : QuicStreamConformanceTests
     {
         protected override QuicImplementationProvider Provider => QuicImplementationProviders.MsQuic;

src/libraries/System.Net.Quic/tests/FunctionalTests/QuicStreamTests.cs

@@ -718,8 +718,13 @@ public QuicStreamTests_MockProvider(ITestOutputHelper output) : base(output) { }
     }
 
     [ConditionalClass(typeof(QuicTestBase<MsQuicProviderFactory>), nameof(QuicTestBase<MsQuicProviderFactory>.IsSupported))]
+    [Collection("NoParallelTests")]
     public sealed class QuicStreamTests_MsQuicProvider : QuicStreamTests<MsQuicProviderFactory>
     {
         public QuicStreamTests_MsQuicProvider(ITestOutputHelper output) : base(output) { }
     }
+
+    // Define test collection for tests to avoid all other tests.
+    [CollectionDefinition("NoParallelTests", DisableParallelization = true)]
+    public partial class NoParallelTests { }
 }