Stack tool 32/64 bit compatibility fixes.

Left the default symbol.ARCH value intact and changed stack_core instead
so that it will assume the ABI is arm until it sees an ABI line.  This
allows compatibility for people who are used to pasting portions of a
tombstone instead of the whole thing (assuming said tombstone is arm)
while additionally supporting other architectures if a whole tombstone
  is pasted in.

(cherry picked from commit 15142f793a5418be7337846c1b3b628d90716f3e)

Change-Id: Ide73171fc4e513b39bee74e2270252c3b32e23cd
1 file changed