[llvm] [BOLT] Enable standalone build (PR #97130)

[Tristan Ross via llvm-commits]

RossComputerGuy wrote:

@rafaelauler I've now got it to where it copies instead of patching the `getPath` method to grab inside of `ools/bolt/bolt_rt-bins/lib`.

https://github.com/llvm/llvm-project/pull/97130