On reintegrating [integration-tests]

The tag integration-tests has currently only 68 questions, and no tag wiki.

The tag integration-testing has currently 3136 questions in it, and a fairly decent tag wiki.

Both tags mean the same.

I hereby propose to the followings about this tag:
- synonymize integration-tests to integration-testing.
- retag every question using integration-tests to integration-testing.
- retag every question using integration-tests to integration-testing and burninate the former tag.

For complete transparency the source conversation of this question for moderators: http://chat.stackoverflow.com/transcript/message/31328521#31328521