The depthBoundsTest checks if the depth is withing a certain range, and
if not, sets coverage to 0 for the particular fragment.

Tests: dEQP-VK.pipeline.depth.nocolor.format.d16_unorm.compare_ops.*
Tests: dEQP-VK.pipeline.depth.nocolor.format.d32_sfloat.compare_ops.*
Tests: dEQP-VK.pipeline.depth.nocolor.format.d32_sfloat_s8_uint.compare_ops.*
Tests: dEQP-VK.pipeline.depth.nocolor.format.d32_sfloat_s8_uint_separate_layouts.compare_ops.*
Tests: dEQP-VK.dynamic_state.ds_state.depth_bounds_1
Tests: dEQP-VK.dynamic_state.ds_state.depth_bounds_2
Tests: dEQP-VK.rasterization.frag_side_effects.color_at_end.depth_bounds
Tests: dEQP-VK.rasterization.frag_side_effects.color_at_beginning.depth_bounds

Bug: b/181656417
Change-Id: I50076834afa21f5b93e59b27a5438ba26f8008c8
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/53888
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Sean Risser <srisser@google.com>
Commit-Queue: Sean Risser <srisser@google.com>