Move from libbacktrace libunwindstack.

libbacktrace is deprecated, so use the new unwindstack object
that replaces this.

Bug: 120606663

Tag: #refactor

Test: Manual - Ran bluetooth_stack_with_facade sent SIGSEGV and
Test: observed valid backtrace (on host and device).
Test: Ran root-canal on host and sent SIGSEGV and observed valid
Test: backtrace (host only executable).
Change-Id: I5c95627b3f674495e0d9d022d2efff1da5ccefc
(cherry picked from commit ae29ca0c)
Merged-In: I5c95627b3f674495e0d9d022d2efff1da5ccefc5

Change-Id: I690e23c4eadd7a9e3f33eb246f4458d23eb03df0
Merged-In: I690e23c4eadd7a9e3f33eb246f4458d23eb03df0
(cherry picked from commit 64be1dcc)