Regression pwnable_collision

[ekilmer]

With the latest release of Manticore (v0.3.2 released Nov 11, 2019), the [pwnable_collision] test now fails.

Relevant CI runs:

• Last passing: https://travis-ci.org/trailofbits/manticore-examples/builds/610150495
• First failure: https://travis-ci.org/trailofbits/manticore-examples/builds/610671213

After some investigation, I believe the issue is with a SMT simplification pass that hangs when running with python test.py, but it does not hang when running with nosetests (for some unknown reason).