Remove hack to suppress pseudo element names.

Previously we suppressed the pseudoElement names in order to avoid rebaselines.
Those are easy now, so fix the names.

BUG=416453

Review URL: https://codereview.chromium.org/645623003

git-svn-id: svn://svn.chromium.org/blink/trunk@183505 bbb929c8-8fbe-4397-9dbb-9b2b20218538