[llvm] [BOLT] [NFC] Eliminate uses of throwing std::map::at (PR #92950)

[Amir Ayupov via llvm-commits]

https://github.com/aaupov approved this pull request.

Thanks! Looks good with one suggestion – please see if you can address it in reasonable time. Otherwise we can proceed with landing as is.

Also please remove a space between "[BOLT]" and "[NFC]".

https://github.com/llvm/llvm-project/pull/92950