[webapi] Change the promise cases to auto tests

Impacted tests(approved): new 0, update 0, delete 0
Unit test platform: [Android]
Unit test result summary: pass 4, fail 0, block 0
Merge pull request #652 from zhuyongyong/yongzhu/webapi/promise-auto

[webapi] Change the promise cases from menual tests to auto tests
[misc] Add testapp to web-mbat-tests

[Detailed commit message (if have)]
Impacted TCs num(approved): New 0, update 4, deleted 0
Unit test platform: [tizen]
Unit test result summary: Pass 4, Fail 0, Blocked 0
Merge pull request #622 from linshen/update-mbat

[misc] Add testapp to web-mbat-tests