[llvm] [RISCV][VLOPT] Support segmented store instructions (PR #155467)

[Min-Yih Hsu via llvm-commits]

================

----------------
mshockwave wrote:

> Can we also add an LLVM IR test in vl-opt.ll?

Done, I added a test to make sure we peekthrough llvm.riscv.tuple_insert. Other cases should be covered by tests in vl-opt-op-info.mir

https://github.com/llvm/llvm-project/pull/155467