Follow-up to r85240:

Follow-up to r85240:

* Don't stub RequestContext.  The chances of us getting away without needing to access *any* of the six major globals is nil, and in the meantime it's screwing up strong function typing and throwing catchable fatals everywhere.

* Stop stubbing $wgOut.  The only path where we can avoid unstubbing it is if we immediately die due to maxlag overflow, and that's a) a pretty uncommon code path, and b) a DB issue which won't be affected by a tiny bit of extra apache load.  That allows us to do strong typing on function parameters with it, which is a Good Thing (TM).

Also make OutputPage::getContext() private; I'm not convinced that a context belongs here (it's *part of* the context, not a consumer of it), let's work through it a it more before we advertise its existence.