[llvm-branch-commits] [AArch64] Remove usage of PostRAScheduler (PR #92871)

[Pengcheng Wang via llvm-branch-commits]

https://github.com/wangpc-pp created https://github.com/llvm/llvm-project/pull/92871

This doesn't take effect as we have overrided `enablePostRAScheduler`
and we should use the `FeaturePostRAScheduler` feature in processor
definitions.