[llvm] [AArch64] Skip storing of stack arguments when lowering tail calls (PR #126735)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> These truncations don't appear in SDAG and may not preserve the loaded value so we can't simply skip over them.

The GlobalISel call lowering should essentially mirror what the DAG did. It probably should not have started by emitting the extending load, and emitted a non-extending s8 load with the assert_zext on the s8 value 

https://github.com/llvm/llvm-project/pull/126735