verifier: Bypass monitor-{enter,exit} depth checks

Per Google Bug 61916[1], the monitor-enter and monitor-exit checks in
dex2oat are excessively strict and will reject some valid APKs, such as
WhatsApp[2].  This change attempts to relax those requirements.

[1] https://code.google.com/p/android/issues/detail?id=61916
[2] http://forum.xda-developers.com/showthread.php?t=2525044

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
tools: use '/usr/bin/env python' instead of '/usr/bin/python'

* This is how it is done in other scripts in the AOSP tree, as
  '/usr/bin/python' may be python3 on some distros, which isn't
  supported yet.

Change-Id: I0d9857fc6a122f505953fddcd6244dad75b1838a