[wrt][xwalk-2064] Fix No test cases shown when running wrt-i18n-tizen-tests

- Add testcase in tests.xml
Merge pull request #401 from wanghongjuan/wanghongjuan/wrt/xwalk-2064

[wrt][xwalk-2064] Fix no test cases shown when running wrt-i18n-tizen-tests