PHPUnit: Add Database tags
Several unit tests access the database, but did not declare
themselves in the Database @group. This causes
"make databaseless" to fail needlessly. Add the
missing tags.
tests/phpunit/includes/LinkerTest.php
tests/phpunit/includes/actions/ActionTest.php
tests/phpunit/includes/specials/ImageListPagerTest.php
tests/phpunit/includes/specials/SpecialMIMESearchTest.php
tests/phpunit/includes/title/MediaWikiPageLinkRendererTest.php
Other than ActionTest.php, these also are problematic in 1.23
Change-Id: I7c1c957e2194c13e48b7ba68d7529e5d89901875