Fix some of the common test collection issues. (#21340)

* Remove old  performance tests that we haven't been running.

As far as I can tell, these tests to capture HAR files were created 5
years ago and not being run as a part of our suite?  They capture HAR
data that we do nothing with so even if they were running we should
remove them until we're ready to care about consuming this kind of
information.

* Update password test unicode string.
* Add ugettext translation helper function.
* Fix lambda syntax that is not valid in python 3.
* Fix ur raw strings which his not valid in python 3
* Use edx_six.get_gettext instead of ugettext.
* Fix a few other encoding issues.
* Don't use old form of sorted funciton.

This form which uses a 'cmp' method is not available in python 3.