Re-enable SpeechRecognitionEvent test

[blois]

Had to be disabled because of Chrome bugs:
https://code.google.com/p/chromium/issues/detail?id=246329
https://code.google.com/p/chromium/issues/detail?id=253902

Issue has been fixed in daily builds but repros in Stable.

[efortuna]

Removed this from the M6 milestone.
Added this to the Later milestone.

[kevmoo]

Removed Area-HTML label.
Added Area-Library, Library-Html labels.

[kasperl]

Removed this from the Later milestone.
Added Oldschool-Milestone-Later label.

[kasperl]

Removed Oldschool-Milestone-Later label.