[llvm] [KeyInstr] Add fields to DILocation behind compile time flag (PR #133477)

[Orlando Cazalet-Hyams via llvm-commits]

OCHyams wrote:

> It looks like this has a large compile-time impact even with the option disabled: https://llvm-compile-time-tracker.com/compare.php?from=d33c6764680ed78ffe824a83b6a33c0b609bafce&to=0c7c82af230bd525bb96a54ca9480797b5fa2a42&stat=instructions:u For some reason it's particularly bad for the stage2 `-O0` builds with a 4.5% regression on sqlite3 (only 1% for stage1).

Thanks @nikic, that is unexpected, I'll look into this today

https://github.com/llvm/llvm-project/pull/133477