Excessive multisample option mishandled on Windows

[parasti]

Tracking this here, so we don't forget.

http://forum.nevercorner.net/viewtopic.php?id=2803

In short, creating an OpenGL context with an excessive number of samples fails on Linux (as expected by our fallback path), but succeeds on Windows, returning a weird, basically unusable, context.

This is an SDL bug (by way of being a platform inconsistency). It seems they attempted to fix this years ago, but aren't handling every case. Possibly relevant Bugzilla thingy:

https://bugzilla.libsdl.org/show_bug.cgi?id=77