Microdumps: support aarch64 and lib mapping from APK

- Filter modules by prot flags (only +x) not extensions. It wouldn't
  otherwise catch the case of Chrome mapping the library from the
  apk (which is mapped r-x but doesn't end in .so).
- Use compile-time detection of target arch, in order to cope with
  multilib OSes, where uname() doesn't reflect the run-time arch.
- Add OS information and CPU arch / count.
- Add support for aarch64.
- Add tests and stackwalk expectations for aarch64.
- Fix a potential overflow bug in the processor.
- Rebaseline the tests using smaller symbols.
- Fix microdump_writer_unittest.cc on 32-bit host.

BUG=chromium:410294

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1407 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/processor/microdump_stackwalk_test

@@ -29,9 +29,15 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+source "${0%/*}/microdump_stackwalk_test_vars"  # for MICRODUMP_SUPPORTED_ARCHS.
 testdata_dir=$srcdir/src/processor/testdata
-./src/processor/microdump_stackwalk $testdata_dir/microdump.dmp \
-                                   $testdata_dir/symbols/microdump | \
- tr -d '\015' | \
- diff -u $testdata_dir/microdump.stackwalk.out -
-exit $?
+
+set -e  # Bail out with an error if any of the commands below fails.
+for ARCH in $MICRODUMP_SUPPORTED_ARCHS; do
+  echo "Testing microdump_stackwalk for arch $ARCH"
+  ./src/processor/microdump_stackwalk $testdata_dir/microdump-${ARCH}.dmp \
+                                      $testdata_dir/symbols/microdump | \
+   tr -d '\015' | \
+   diff -u $testdata_dir/microdump.stackwalk-${ARCH}.out -
+done
+exit 0