[Piglit] [PATCH V2 0/8] Add tests for ARB_texture_multisample

[Chris Forbes]

This series adds tests for the ARB_texture_multisample extension.

Big changes from V1:
    * Varying sample counts are supported (trys 2/4/6/8/16/32 samples)
    * All new samplers are tested, rather than just sampler2DMS
    * Existing texelFetch test is beefed up to handle the new samplers
        rather than writing new ones.

I think the texelFetch changes could be tidier -- perhaps we need some
piglit_draw_rect()-style helpers which work in core contexts?

This shows up a bit of remaining breakage on Gen7 i965, where texelFetch()
in the fragment shader produces garbage with all of these new samplers.

-- Chris