Changeset 51122 for trunk/tests/phpunit/tests/media/getPreviousImageLink.php

Media: Add new functions to return the previous/next attachment links.

New functions:

• get_adjacent_image_link()
• get_next_image_link()
• get_previous_image_link()

Fixes #45708.

Props flixos90, DrewAPicture, mor10, antpb, hellofromTonya, whyisjake.