[llvm] [RISCV] Simplify (srl (and X, Mask), Const) to TH_EXTU (PR #102802)

[Wang Yaduo via llvm-commits]

MouseSplinter wrote:

> @MouseSplinter do you have commit access?

Yes, but I notice a strange [CI fail](https://buildkite.com/llvm-project/github-pull-requests/builds/90710#019145c2-81cd-4dc4-8500-e443d5746345) , do you know how to resolve it?

https://github.com/llvm/llvm-project/pull/102802