Pass unclamped fragcoord.z to shader
Pass unclamped fragcoord.z to shader

The Vulkan spec is being clarified to explain that the FragCoord passed
to a shader should use the unclamped depth value and that only the depth
test and depth write should use clamped values.

Bug: b/184063472
Change-Id: Ic76c13512745abea2181475eff5147134a1bf147
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/54668
Kokoro-Result: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Tested-by: Sean Risser <2d04e98eeaa433fb55534399ab3ab2c06fdf7967@google.com>
Reviewed-by: Alexis Hétu <1c7141772178a7e80858c3db5052b328076f08f4@google.com>
Reviewed-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@google.com>
Commit-Queue: Sean Risser <2d04e98eeaa433fb55534399ab3ab2c06fdf7967@google.com>

google/swiftshader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,google/swiftshader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,google/swiftshader,bkaradzic/SwiftShader