[Piglit] [PATCH V2 0/2] Tidy up max-samples testing

[Chris Forbes]

These two patches tidy up some edge cases in checking sample count
limits for renderbuffers and multisample textures.

1/2 simply skips testing the EXT_framebuffer_multisample behavior if
a newer extension is supported which overrides it.

2/2 introduces a new test for the limits required by ARB_texture_multisample.
This is skipped if ARB_internalformat_query is supported, which redefines
the sample count limit check again.

-- Chris