Fix race condition in DacEnumerableHashTable::BaseFindNextEntryByHash

[AntonLapounov]

See #75041 (comment) for details. Fixes #75041.

[VSadov]

I think VolatileEntry needs to be renamed just an Entry. The name seems deceiving.

[VSadov]

Or perhaps m_pNextEntry should be declared as volatile - in "ISO volatile" sense. I generally prefer explicit VolatileLoadWithoutBarrier as more obvious at the point of reading, but if all the places where we read m_pNextEntry need to be changed and there are lots of them, maybe volatile would work better.
Perhaps that is what was meant when the type got "Volatile" in its name and we lost it somehow.

[AntonLapounov]

The failure in the 'Build OSX x64 release NativeAOT' job is #75005.

[AntonLapounov]

but if all the places where we read m_pNextEntry need to be changed and there are lots of them, maybe volatile would work better.

Volatile loads are not necessary on the writer code path. I tried to make a safest/easiest fix for porting to 7.0. Do the changes look reasonable?

[AntonLapounov]

/backport to release/7.0

[github-actions]

Started backporting to release/7.0: https://github.com/dotnet/runtime/actions/runs/3004820401