test: investigate Windows net10 Serialization test host crash

Summary

The Windows net10 BVT lane intermittently crashed the Orleans.Serialization.UnitTests test host without reporting a failed test.

Evidence

• PR: #11168
• Workflow run: https://github.com/dotnet/orleans/actions/runs/34071827542
• Failed job: https://github.com/dotnet/orleans/actions/runs/34071827542/job/101590479015
• Assembly: Orleans.Serialization.UnitTests.dll (net10.0|x64)
• Exit code: 7 (test host process crash)
• TRX counters: 105 executed, 105 passed, 0 failed, 0 aborted
• A full dump and crash sequence log were uploaded in artifact test_output_test_BVT_windows-latest_net10.0

The crash sequence ended after SerializerServiceProviderLifetimeTests.PooledSerializerStateCanBeReturnedAfterServiceProviderDisposal started. Dump inspection found no current managed exception. The active managed stack was constructing serializer services through TypeConverter.ConsumeMetadata; it did not show a failing assertion or an exception from the copier changes in #11168.

The exact test passed 20 consecutive local net10 runs on the PR head. The complete net10 Orleans.Serialization.UnitTests project also passed locally (4,216 tests), and the parallel Linux net10, Windows net8, and all other CI lanes passed.

This does not match the coverage-profiler initialization failure previously tracked by #10824: coverage initialized, test execution progressed normally, and this run produced a test-host crash dump.