DevTools: get rid of Element.prototype.removeMatchingStyleClasses

This method encourages className crafting and runs unexpectedly long.

BUG=316092

Review URL: https://codereview.chromium.org/466703002

git-svn-id: svn://svn.chromium.org/blink/trunk@180163 bbb929c8-8fbe-4397-9dbb-9b2b20218538