[Bluetooth TCT] move some assertion checks

Some TCT test cases verify that Web API returns 'undefined'.
In few cases, this check is done in the Web API callback and
so before the Web API has returned 'undefined'.

BUG=XWALK-2090
[misc][wrt] Update usecase common
[wrt] Add new suite for wrt-manifest-android-tests
Merge pull request #420 from clecou/bluetooth_asserts

[Bluetooth TCT] move some assertion checks
Merge pull request #452 from wanghongjuan/wanghongjuan/misc/common

[misc][wrt] Update usecase common
Merge pull request #458 from kangxu/kangxu/wrt/wrt-manifest-android-tests/new

[wrt] Add new suite for wrt-manifest-android-tests