[clang] [llvm] [clang] Add regalloc PBQP for all targets in clang (PR #166645)

[Lang Hames via llvm-commits]

lhames wrote:

@Zararest -- seems reasonable to me. I believe that we used to offer it on all platforms.

Out of interest: Did you check what this does to the size of the clang binary?

https://github.com/llvm/llvm-project/pull/166645