Fixed an assert related to MediaQuerytokenizer code points table

The assert was a result of an off-by-one error in both the array's definition and the assert itself.

BUG=353577

Review URL: https://codereview.chromium.org/203343004

git-svn-id: svn://svn.chromium.org/blink/trunk@169494 bbb929c8-8fbe-4397-9dbb-9b2b20218538