[removed] multiple browsers from Karma local testing
[removed] multiple browsers from Karma local testing

Summary: We can run multiple browsers in CI, but it's just distracting clutter to run them all locally.

Reviewers: O3 Material JavaScript platform reviewers, #material_motion, O2 Material Motion, featherless

Reviewed By: #material_motion, O2 Material Motion, featherless

Tags: #material_motion

Differential Revision: http://codereview.cc/D2398

material-motion/material-motion-js,material-motion/material-motion-js,material-motion/material-motion-js