[llvm] CodeGen: Eliminate dynamic relocations in the register superclass tables. (PR #119122)

[Chandler Carruth via llvm-commits]

chandlerc wrote:

Just to give some motivation, this PR (after #118734 merges) will remove another 13% of non-vtable dynamic relocations from the `clang` binary -- that's over 10k dynamic relocations avoided.

These are also hard to see as no *one* table is terribly large, but there are a large number of them.

There are also more opportunities remaining here, notably the dynamic relocations required in some of the `.*SysRegList` arrays and the `<target>MCRegisterClasses` arrays.

Also, could the same change done here for superclass tables be done for subreg tables? That's the other one that seems to show up as a lot of separate tables, although not as much as superclasses.

https://github.com/llvm/llvm-project/pull/119122