mediawiki.util.test: Suppress deprecation notice for jsMessage

* Hide the false positive when running the QUnit test suite.
* Clean up documentation comment (tag order) for consistency
  with the rest of the code base.

Follows-up Ib41d5245682552, I211593629ca2.

Change-Id: Iac42aef26f78b5637e5aaafb6fc48e60e9ea0e3f
Merge "mediawiki.util.test: Suppress deprecation notice for jsMessage"