Update cocos2dx/platform/ios/CCFileUtils.mm

fix the problem when calling CCFileUtils::sharedFileUtils()->getFileData("a.png") doesn't work.
Merge pull request #1862 from Horcruxes/master

getFileData("a.png") doesn't work on iOS.
Updated the submodule reference of cocos2d-js-tests.
Added Scale9Sprite js tests.
Merge pull request #1865 from dumganhar/master

Updated the submodule reference of cocos2d-js-tests.