Fixes#5887. It seems there's some sort of issue in CPython where it
can get confused into thinking a `.pyc` file that's actually stale is
up to date -- perhaps when they date from the same second, say from
the middle of a rebase.
For now, rather than dig further to fix this properly and be sure of
having really done so, just go back to wiping out all `.pyc` files.
The impact is about 1s; that's noticeable when running a short test
file on a quad-core machine (about 8s), but not so much on a more
typical dev machine or on a larger set of tests.
This optimizes .pyc files removal.
Instead of removing all pyc files, it will only remove pyc files where
corresponding py file is not found. This saves about 1s in the
startup time of `run-dev.py` (and thus also `test-js-with-casper`).
Fixes#5760.
Greg Price
Tim Abbott
Abdul Qabiz
Eklavya Sharma
Vladislav Manchev
Tim Abbott
Keegan McAllister