This CL cleans up references to base/max level bug and fixes
one lingering issue regarding special handling of depth/z for
arrayed surfaces.

Bug: angleproject:3148
Bug: angleproject:3184
Bug: angleproject:3948
Bug: angleproject:3949
Bug: angleproject:3950
Test: dEQP-GLES3.functional.texture.mipmap.*base_level*
Test: dEQP-GLES3.functional.texture.mipmap.*max_level*
Test: Texture2DArrayTestES3.DrawWithLevelsOutsideRangeWithInconsistentDimensions
Change-Id: Iad72005a111507c50b8be9726adc32285bbae52b
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1832757Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Cody Northrop <cnorthrop@google.com>