[llvm] [BOLT][NFC] Extract a function for dump MCInst (PR #67225)

[Maksim Panchenko via llvm-commits]

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

LGTM. Thanks. Small suggestion: `s/dumpInst/dump/` for debugging convenience, but I don't insist.

https://github.com/llvm/llvm-project/pull/67225