As we slowly move away from using globals, overrideConfigValue()
and overrideConfigValues() were introduced as a way to override
test configs between tests.
Under the hood, it just calls setMwGlobals() which resets services,
so take note.
Part 1: Directories covered are: languages/, maintenance/, tests/,
structure/ and includes/Permissions/.
Depends-On: I618b16c6d99c94eb2e7edcf05e888a65f7156754
Change-Id: If56f7d10d79f3a9824a52091a2b544d8653dd7b6
f00cd03580