Update debuggerd for stack MTE.

Two things need changing for debuggerd_test to pass.

 1. The seccomp policy needs to allow for PROT_MTE (0x20) in both
    mprotect() and mmap(). Stack MTE processes do a mprotect()/mmap() of
    the stack when launching a process.
 2. The fault address and stack pointer need to be untagged when trying
    to figure out the stack overflow cause.

Bug: 320448268
Bug: 292478827
Test: atest debuggerd_test --iterations=10
Change-Id: I56471c32ca40edffbb61b7547bdf2b85a6eb1ff7