Skip DllImportSearchPathsTest on wasm

[elinor-fung]

Fixes #84724

[lewing]

dotnet/aspnetcore#47652 it looks like this code gets hit in real life too

[carlossanlop]

Thanks @elinor-fung!

FYI, PR submitters of tell-mode changes (test-only, infra-only) can get their PR automatically unblocked for merging* by adding the Servicing-approved label themselves. This allows the required check-service-label CI action to pass.

*Assuming it's been signed-off and the CI failures are investigated as unrelated, of course.

[lewing]

/backport to release/6.0

[github-actions]

Started backporting to release/6.0: https://github.com/dotnet/runtime/actions/runs/4726085124

[github-actions]

@lewing backporting to release/6.0 failed, the patch most likely resulted in conflicts:

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

Applying: Skip DllImportSearchPathsTest on wasm
Using index info to reconstruct a base tree...
M	src/tests/issues.targets
Falling back to patching base and 3-way merge...
Auto-merging src/tests/issues.targets
CONFLICT (content): Merge conflict in src/tests/issues.targets
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
Patch failed at 0001 Skip DllImportSearchPathsTest on wasm
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".
Error: The process '/usr/bin/git' failed with exit code 128

Please backport manually!

[github-actions]

@lewing an error occurred while backporting to release/6.0, please check the run log for details!

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