Fix dotnet command does not honor "globalPackagesFolder" in nuget.config file

[guoyongchang]

Source Issue:

• dotnet command does not honor "globalPackagesFolder" in nuget.config file #39874

Background

• User nuget.config overrides globalPackagesFolder.
• dotnet tool restore respects the override and places tool binaries in the custom cache, but dotnet tool run still looks in the default location.
• Manifest/shim entries point to that stale path, so the CLI insists on “Run dotnet tool restore…” even immediately after a restore.

Root Cause

• LocalToolsResolverCache.Save only appended new entries. When the same command ID was saved again (after restore into a new cache), the earlier row remained untouched, so the resolver kept resolving to the old executable path.

Fix Summary

• Rework LocalToolsResolverCache.Save to overwrite an existing cache row when the RestoredCommandIdentifier matches, otherwise append a new row.
• Add regression test GivenExecutableIdentifierItUpdatesExecutablePathOnSubsequentSave to confirm the cache returns the freshly saved executable path.

Impact

• Local tools now honor changes to globalPackagesFolder without requiring manual cache cleanup or reinstalling tools.
• dotnet tool run succeeds immediately after restore when the package cache directory moves.

[guoyongchang]

@dotnet-policy-service agree