Change `new XMLHttpRequire()` to `cc.loader.getXMLHttpRequest()` .
Remove `FileTest` then add `LoaderTest` and `PathTest`.
Merge branch 'tests_js_3.0' of https://github.com/cocos2d/cocos2d-js-tests into tests_js_3.0_ccgame
Merge pull request #363 from SmallAiTT/tests_js_3.0_ccgame

issue #3935 Fix some bugs.