[llvm] [RISCV] Support .option (no)autocompress (PR #122483)

[Sam Elliott via llvm-commits]

lenary wrote:

> Thanks for doing this. Kito and I have talked about something similar in the past. .option rvc has been broken since Zca/Zcf/Zcd was introduced.

Yeah. Just like EF_RVC conflates two things (C extension being present and IALIGN=16), `.option norvc` (effectively) conflates two things (C extension being present, and compression patterns being enabled). This is part of the missing work I mentioned that prevented us adding CompressPats to the Xqci work - the other is the tied operand issue that Sudharsan mentioned.

https://github.com/llvm/llvm-project/pull/122483