Fix _Unwind_Backtrace for arm.

The unwind code does not properly update the IP when on arm.

There is still a bug in this unwinding code, it stops unwinding at the
first catch it finds.

Bug: 16874447

(cherry picked from commit 34ce4a6f5c6ffab0fb97be2b62f8e71b14df8fb4)

Change-Id: Ic285e4885f6420584363d1bf4169227c07c05bb9
1 file changed