Updated mediawiki/extensions
Project: mediawiki/extensions/MobileFrontend  ac65651a09959c7f1deec7b628bb7090aaee16fa

Renamed tests/acceptance folder to tests/browser

To make it the same as almost all other repositories that have browser
tests:

https://github.com/wikimedia/mediawiki-selenium#links

Change-Id: I4957a13e520163dc79ed9aec12d68a87a4fc52f2