[llvm] Reapply "RuntimeLibcalls: Use get_host_tool_path for executables used … (#159488) (PR #159489)

[Matt Arsenault via llvm-commits]

arsenm wrote:

https://github.com/llvm/llvm-project/pull/159513 should fix the fuchsia failure, but is stricter than theoretically required 

https://github.com/llvm/llvm-project/pull/159489