[lldb][AArch64] Simplify MTE memory region test

By checking for cpu and toolchain features ahead
of time we don't need the custom return codes.

Reviewed By: omjavaid

Differential Revision: https://reviews.llvm.org/D97684

GitOrigin-RevId: 6cdc2239dbabeb6fb8a9f933693f744a60d50a8c
3 files changed