[lld] [llvm] Add extended mnemonics (PR #97571)

[Dominik Steenken via llvm-commits]

dominik-steenken wrote:

> The CI shows failures in insn-good.s and a bunch of SystemZ LLD tests, these definitely need to be addressed.

I have fixed those tests. In `insn-good.s` some Aliases were pinned to the wrong target instruction, and the *lld* tests needed to be modified to account for `nop` and `nopr` now being emitted by the disassembler.

> Also, can you re-check that all mnemonics added here are also accepted by GAS? I think at least these may not be: nhhr, nhlr, nlhr, ohhr, ohlr, olhr, xhhr, xhlr, xlhr. You should verify that GAS can assemble all the insn-good* files (resulting in mostly identical object files - at least the disassembly of those object files needs to match again).

I moved the extended mnemonics of `R(N|O|X)SBG` to a different PR and re-checked that gas can assemble all of our assembly tests. While doingf that, we discovered an issue with register types in some instructions, as well as a difference in permissiveness regarding the immediate fields with `Z` and `T` bits that will be addressed in separate PRs.

https://github.com/llvm/llvm-project/pull/97571