[lld] [lld][COFF] Emit coffgrp debug record (PR #205630)

[Alexandre Ganea via llvm-commits]

https://github.com/aganea commented:

I feel the PR is going in a good direction. Thank you for documenting also this POGO record. I think nevertheless that the PR needs a bit more touchup and comparaison with what MSVC does. Probably testing the corresponding flags (/LTCG, /GENPROFILE, /USEPROFILE) with a very simple example in MSVC, and trying to match the output with LLD's would be the way to go.

https://github.com/llvm/llvm-project/pull/205630