[llvm] TableGen support for RegisterBankInfo (PR #71357)

[via llvm-commits]

https://github.com/rovka commented:

Could you update [the RegBankEmitter test](https://github.com/llvm/llvm-project/blob/main/llvm/test/TableGen/RegisterBankEmitter.td)?

https://github.com/llvm/llvm-project/pull/71357