[Mesa-dev] i965 query object tidying

[Kenneth Graunke]

I'm hoping to add support for doing the transform feedback queries in
hardware, rather than software counters (as geometry shaders will break
the CPU-side counting.)

Before I could do that, I had to make the query object code a bit more
understandable, and eliminate globals specific to occlusion queries.

I think it's a lot easier to follow now.  A second series will do the
actual new hardware counter support.

No piglit or es3conform regressions on Ivybridge.  No regressions in
oglconform's occlusion_query and occlusion_query2 tests.