Hygiene: Make language browser tests more generic

This may also make the tests in MobileFrontend-en.m.wikipedia.beta.wmflabs.org-linux-chrome Build
pass for the language.feature and language_logged_in.feature as the selector is more forgiving

Change-Id: Ieae191cbd104dd2dd7095a3355f58debfc2548ff
Merge "Hygiene: Make language browser tests more generic"