[llvm] [llvm][NewGVN] Fixing the replacement of incorrect instructions (PR #70599)

[Ben Shi via llvm-commits]

benshi001 wrote:

1. It would be better to add `Fixes #70421` at the end of your commit message, not in this PR.
2. Ask someone who contribute to this file recently, to review your PR.

https://github.com/llvm/llvm-project/pull/70599