Change <video controls=true> to just <video controls> in LayoutTests

This avoids the appearance of the attribute value being important.

NOTRY=true
R=fs@opera.com

Review URL: https://codereview.chromium.org/613153002

git-svn-id: svn://svn.chromium.org/blink/trunk@182905 bbb929c8-8fbe-4397-9dbb-9b2b20218538