remove compositing query asserts disabler

This one seems fixed and doesn't hit any asserts.

BUG=343757
R=ojan

Review URL: https://codereview.chromium.org/168093002

git-svn-id: svn://svn.chromium.org/blink/trunk@167382 bbb929c8-8fbe-4397-9dbb-9b2b20218538