[llvm-branch-commits] MachineInstrBuilder: Introduce copyMIMetadata() function. (PR #133535)

[Peter Collingbourne via llvm-branch-commits]

https://github.com/pcc created https://github.com/llvm/llvm-project/pull/133535

This reduces the amount of boilerplate required when adding a new
field to MIMetadata and reduces the chance of bugs like the
one I fixed in TargetInstrInfo::reassociateOps.