Bogus SynchronizationLockException thrown in thread intensive workloads

[BruceForstall]

In x64 Windows release testing in the CI:

https://ci.dot.net/job/dotnet_coreclr/job/master/job/release_windows_nt

There are many cases of the TryEnter01, TryEnter03, and TryEnter05 tests failing:

https://ci.dot.net/job/dotnet_coreclr/job/master/job/release_windows_nt/3556/
https://ci.dot.net/job/dotnet_coreclr/job/master/job/release_windows_nt/3553/
https://ci.dot.net/job/dotnet_coreclr/job/master/job/release_windows_nt/3549/
https://ci.dot.net/job/dotnet_coreclr/job/master/job/release_windows_nt/3546/
https://ci.dot.net/job/dotnet_coreclr/job/master/job/release_windows_nt/3538/
https://ci.dot.net/job/dotnet_coreclr/job/master/job/release_windows_nt/3586

[BruceForstall]

@kouvel Is this your area?

[kouvel]

Yes I'll take a look

[kouvel]

Closing until another failure occurs, hopefully with more info

[jkotas]

@kouvel We have a pretty reliable repro in real-world workload. I am going to send you details about the repro via email.

[kouvel]

Thanks, that helped greatly. Should be fixed by dotnet/coreclr#16089.

[kouvel]

Reopening for release/2.1 PR dotnet/coreclr#16093

[kouvel]

Fixed by dotnet/coreclr#16093