[llvm] [AArch64] Remove redundant COPY from loadRegFromStackSlot (PR #107396)

[via llvm-commits]

DTeachs wrote:

> This removes a redundant 'COPY' instruction that #81716 probably forgot to remove.
> 
> This redundant COPY led to an issue because because code in LiveRangeSplitting expects that the instruction emitted by `loadRegFromStackSlot` is an instruction that accesses memory, which isn't the case for the COPY instruction.

Seems to be the case. Should this be backported to 19.x if this is causing issues?

https://github.com/llvm/llvm-project/pull/107396