To prevent hitting a known issue with dart2js and bitwise operators
(http://stackoverflow.com/questions/17427976/bitwise-operations-wrong-result-in-dart2js),
use arithmetics operators for the result of the "binarySearch" method.
Re-enable json parser tests.
Merge pull request #3186 from rpaquay/fix-binary-search

Workaround dart2js issue and re-enable json parser test