Teach test.py how to call remove_orphaned_pycs.py
Teach test.py how to call remove_orphaned_pycs.py

Even though remove_orphaned_pycs is called by gclient runhooks
it's very common that I will run 'git pull --rebase' and forget
to runhooks, and then end up with a stale pyc file in my
infra directory which will cause test.py to fail in strange ways.

I tested before and after and test.py reported the same (20s) testing
time with and w/o pyc files.

Review URL: https://codereview.chromium.org/516683003

nicko96/Chrome-Infra,nicko96/Chrome-Infra,nicko96/Chrome-Infra,nicko96/Chrome-Infra,nicko96/Chrome-Infra