Round MAX_LOD / MIN_LOD values correctly according to section 6.1.2
of GLES 3.0.4, and add code for COMPARE_MODE and COMPARE_FUNC.

BUG=angleproject:1101
TEST=dEQP-GLES3.functional.state_query.texture.* (all pass),
     dEQP-GLES3.functional.state_query.sampler.* (all pass)

Change-Id: I6043c308c23997513d5de70510a0267419dd1868
Reviewed-on: https://chromium-review.googlesource.com/330112Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>