[compiler-rt] [compiler-rt] Add baremetal version of profile library. (PR #167998)

[Mr. Walls via llvm-commits]

https://github.com/reactive-firewall commented:

LGTM; with the already discussed caveat that there is room for future improvements. 

Specifically I like the additional comments for developers.

Hope this helps

https://github.com/llvm/llvm-project/pull/167998