[Android] Fix unable to get the "messaging" permission on Android OS

Fix three errors.
1) Move addEventListener from "messaging" to "messaging.sms".
2) Each PendingIntent should have different requestCode to identify itself. If
use same code, the extra data field of PendingIntent instance will be replaced
by the new one. Then system calls the intent callback function only once.
3) In unit test page, check operation should be put into Promise callback
function. If just put them right under the send operation, in emulator, the
send operation can put message in database so fast, that the check operation
is succeed every time. But in geek, because the send operation is async and
slow. The check operation is always failed.

Re-indent code in unit test page.

BUG=https://crosswalk-project.org/jira/browse/XWALK-940