Fix a bunch of version / GLSL / extension requirement problems

These have been sitting in my local tree for, literally, years. I first authored them when I was trying to do some r200 and i915 work... way back before working on old drivers was cool.

The Fix many incorrect GLSL checks won't matter for current Mesa as every remaining drivers support both vertex and fragment shaders all the time. I used that commit several times to enable testing on r200.

I'm reviving this now because I started working on another MR that interacted with some of these changes. I'd like to land this before I send up that MR.