Windows C# test crashes with "assertion failed: queue.Pop() == nullptr" #27062
Description
Spotted as a flake on a PR test.
Test Files
T:/src/github/grpc/workspace_csharp_windows_opt_native/src/csharp/Grpc.Core.Tests/bin/Release/net45/Grpc.Core.Tests.exe
Test Filters
Test: Grpc.Core.Tests.ContextualMarshallerTest
=> Grpc.Core.Tests.ContextualMarshallerTest.RequestSerializationError_BlockingUnary
D0816 01:39:19.640625 Grpc.Core.Internal.UnmanagedLibrary Attempting to load native library "T:\src\github\grpc\workspace_csharp_windows_opt_native\src\csharp\Grpc.Core.Tests\bin\Release\net45\grpc_csharp_ext.x64.dll"
D0816 01:39:19.734375 Grpc.Core.Internal.NativeExtension gRPC native library loaded successfully.
=> Grpc.Core.Tests.ContextualMarshallerTest.ResponseParsingError_UnaryResponse
E0816 01:39:20.375000 0 T:\src\github\grpc\workspace_csharp_windows_opt_native\src\core\lib\surface\server.cc:201: assertion failed: queue.Pop() == nullptr