Process minidumps generated on ARM64 in iOS apps.

Patch by Colin Blundell <blundell@chromium.org>

BUG=542

Review URL: https://breakpad.appspot.com/704002/


git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1236 4c0a9323-5329-0410-9bdc-e9ce6186880e