[Android] Fix the issue of enabling remote debugging in packaging tool.

Since when there is available manifest.json file, it is used by default,
while remote debugging cannot work after the application is packaged with
--enable-remote-debugging. This patch fixes this issue by removing the
related code of disabling remote debugging in packaging tool. Add the
corresponding test case.

BUG=https://crosswalk-project.org/jira/browse/XWALK-933