[llvm] [llvm-exegesis] Debug generated disassembly (PR #142540)

[Sjoerd Meijer via llvm-commits]

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

I like the output and think this will be very useful to me. Ideally I would like to have this available in a release build without assertions, but let's get some experience first before we promote this to an option, so LGTM.

I've left two nits that don't need another review if addressed. 

https://github.com/llvm/llvm-project/pull/142540