[Driver] Bring back "Clean up Debian multiarch /usr/include/<triplet> madness"

This reverts commit aae84b8e3939e815bbc1e64b3b30c0f10b055be4.

The chromium goma folks want to use a Debian sysroot without
lib/x86_64-linux-gnu to perform `clang -c` but no link action. The previous
commit has removed D.getVFS().exists check to make such usage work.

GitOrigin-RevId: 35dd6470de847636c212d7e0cd4d7ac2995679cc
1 file changed