Disable MF/VE jobs moved to SauceLabs

browsertests-MobileFrontend-en.m.wikipedia.beta.wmflabs.org-linux-firefox
browsertests-MobileFrontend-en.m.wikipedia.org-linux-firefox
browsertests-VisualEditor-en.wikipedia.beta.wmflabs.org-linux-firefox
browsertests-VisualEditor-test2.wikipedia.org-linux-firefox

Keep browsertests-MobileFrontend-test2.m.wikipedia.org-linux-firefox
around though.

Change-Id: I210f3b97204abb516795c526cc3c87baa0d6d751