Support AArch64/Linux watchpoint on tagged addresses

AArch64 architecture support virtual addresses with some of the top bits ignored.
These ignored bits can host memory tags or bit masks that can serve to check for
authentication of address integrity. We need to clear away the top ignored bits
from watchpoint address to reliably hit and set watchpoints on addresses
containing tags or masks in their top bits.

This patch adds support to watch tagged addresses on AArch64/Linux.

Reviewed By: DavidSpickett

Differential Revision: https://reviews.llvm.org/D101361