[wrt-usecase][xwalk-1947] Update TC steps

Impacted TCs num(approved): New 0, Update 1, Delete 5
Unit test Platform: Android
Android test result summary: Pass 1, Fail 0, Block 0
Merge pull request #912 from wanghongjuan/wanghongjuan/usecase/xwalk-1947

[wrt-usecase][xwalk-1947] Update TC steps