[Android] Enable instrument test for Contacts API.

Enable instrument test for Contacts API. And, fixed some issues in
contacts test case. The callback function of Promise is invoked after
oncontactchanges(). So, testNewContactFlag will be false. The test
always fail.
You can set ·testRemovedSecondFlag· to `true` here.

As test for `contacts.oncontactschange` has removed, this `removedID` array is not needed anymore.