[llvm] [RISCV][CFI] add function epilogue cfi information (PR #110234)

[via llvm-commits]

dlav-sc wrote:

I added `CFIFixup` pass and regenerated tests: https://github.com/llvm/llvm-project/pull/110234/commits/6ce13ca63f732476b4008a9d80ce41e17d19746d and https://github.com/llvm/llvm-project/pull/110234/commits/2d2395830828d32dd62b7be627b3d0d66e56b546. I've also tried to disable shrink-wrap in `branch_and_tail_call` test (https://github.com/llvm/llvm-project/pull/110234/commits/63ddb103fc5cf7f30fe86c105fb34d5d182b161a) to make sure that it will work without the optimization.

@topperc @kito-cheng could you take a look, please?

https://github.com/llvm/llvm-project/pull/110234