[clang] Reland [Driver] Add support for GCC installation detection in Baremetal toolchain (PR #145390)

[Garvit Gupta via cfe-commits]

quic-garvgupt wrote:

> > Triggering a force build will help verify that the fix is effective and does not cause any further buildbot failures. Please ensure that PR #145390 and PR #144649 are applied in sequence to avoid any merge conflicts
> 
> I couldn't apply the patch for 144649 after the patch for 145390 at head; it looks like there were conflicts. Would it be possible to fix this up first?

Hi, I’ve resolved the merge conflicts on #144649 by first pushing the commit introduced in this PR, followed by the actual required changes. However, only the second commit (9c28666) is necessary to trigger a force build. Therefore, the first commit (296df79) from this PR and the second commit (9c28666) from #144649 are required for the force build and hopefully this should address and resolve all the conflicts.

Please let me know if this would work. Thanks again for the assistance!

https://github.com/llvm/llvm-project/pull/145390