[llvm] [RISCV] Check vmerge's true is in same block in vmerge -> vmv.v.v peephole (PR #110861)

[Harald van Dijk via llvm-commits]

https://github.com/hvdijk approved this pull request.

Thanks for the quick action, have run this against my original non-reduced testcase and can confirm that also works with your PR.

https://github.com/llvm/llvm-project/pull/110861