[misc] Recover test files integrated from Blink LayoutTests

- https://github.com/crosswalk-project/blink-crosswalk/tree/master/LayoutTests
- https://github.com/crosswalk-project/crosswalk-test-suite/pull/635
[misc] Update navigator.language test files

to reflect current being code structure
[misc] Describe why need tests for NavigatorLanguage
Merge pull request #658 from zqzhang/zqzhang/pr635

[misc] Polish #635 of the NavigatorLanguage tests