[misc-xwalk] Add test cases of NavigatorLanguage.

-Fail Reason: Cannot read property 'setAcceptLanguages' of undefined at Object

Impacted tests(approved): New 1, Update 0, Delete 0
Unit test platform: [Android]
Unit test result summary: Pass 0, Fail 1, Block 0
I guess you integrate (not create) the https://github.com/crosswalk-project/blink-crosswalk/blob/master/LayoutTests/navigator_language/navigator_language.html as I mentioned in https://crosswalk-project.org/jira/browse/XWALK-2242

Why not put the test file into `res\` as WebAudio does?