[llvm-branch-commits] [CodeGen][NFC] Remove RegisterClasses pointer array (PR #207204)

[Alexis Engelke via llvm-branch-commits]

https://github.com/aengelke created https://github.com/llvm/llvm-project/pull/207204

All MCRegisterClasses are stored consecutively in memory. Therefore, we
can remove the RegisterClassses pointer array and save 17kiB in
.data.rel.ro.