[llvm] [LLVM][MemCpyOpt] Unify alias tags if we optimize allocas (PR #129537)

[Gabriel Baraldi via llvm-commits]

gbaraldi wrote:

So the original non minimized code is this. I've had some issue fully minimizing it without losing the behaviour https://godbolt.org/z/7jaanfTqM. And on trunk we are removing noalias in both memcpies but not the other aliasing stuff

https://github.com/llvm/llvm-project/pull/129537