[llvm] [TargetLowering] Deduplicate choosing InlineAsm constraint between ISels (PR #67057)

[via llvm-commits]

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

Overall looks good to me.
I feel we miss one check for OOB or an assert around the loop I highlighted.

https://github.com/llvm/llvm-project/pull/67057