[llvm] [MCP] Enhance MCP copy Instruction removal for special case(reapply) (PR #74239)

[via llvm-commits]

LWenH wrote:

> Can you change the description to be a revert of the revert (or reapply)? I would also find it easier to read this if it were split into the original revert plus the version with the bug fix and test

Sure, I separated the description of the original patch and this bug fix path and tried to make it more easy to read:-)

https://github.com/llvm/llvm-project/pull/74239