Fix HashSet copy constructor handling of instances that have fallen back to the randomized hashcode generator.

[eiriktsarpalis]

Fix #107222.

[eiriktsarpalis]

/backport to release/9.0

[github-actions]

Started backporting to release/9.0: https://github.com/dotnet/runtime/actions/runs/10812144574

[github-actions]

@eiriktsarpalis backporting to release/9.0 failed, the patch most likely resulted in conflicts:

$ git am --3way --empty=keep --ignore-whitespace --keep-non-patch changes.patch

Applying: Fix HashSet copy constructor handling of instances that have fallen back to the randomized hashcode generator.
.git/rebase-apply/patch:45: trailing whitespace.
  
warning: 1 line adds whitespace errors.
Using index info to reconstruct a base tree...
M	src/libraries/System.Collections/tests/System.Collections.Tests.csproj
Falling back to patching base and 3-way merge...
Auto-merging src/libraries/System.Collections/tests/System.Collections.Tests.csproj
CONFLICT (content): Merge conflict in src/libraries/System.Collections/tests/System.Collections.Tests.csproj
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config advice.mergeConflict false"
Patch failed at 0001 Fix HashSet copy constructor handling of instances that have fallen back to the randomized hashcode generator.
Error: The process '/usr/bin/git' failed with exit code 128

Please backport manually!

[github-actions]

@eiriktsarpalis an error occurred while backporting to release/9.0, please check the run log for details!

Error: git am failed, most likely due to a merge conflict.