[clang] [Clang][RISCV] Add assumptions to vsetvli/vsetvlimax (PR #79975)

[Kito Cheng via cfe-commits]

kito-cheng wrote:

I guess we need add that at RVVEmitter::createBuiltins at RISCVVEmitter.cpp?

[1] https://github.com/llvm/llvm-project/blob/main/clang/utils/TableGen/RISCVVEmitter.cpp#L418
[2] https://github.com/llvm/llvm-project/blob/main/clang/include/clang/Basic/Builtins.h#L122-L124
[3] https://github.com/llvm/llvm-project/blob/main/clang/include/clang/Basic/BuiltinsARM.def#L32

https://github.com/llvm/llvm-project/pull/79975