According to the Vulkan 1.2 spec:
"For fixed-point depth buffers, fragment depth values are
 always limited to the range [0,1] by clamping after depth
 bias addition is performed. Fragment depth values are
 clamped even when the depth buffer uses a floating-point
 representation."

So, unless the VK_EXT_depth_range_unrestricted extension
is enabled, clamping should always occur.

Bug: b/152634772
Change-Id: I2aee2aeb91efed7399580689fc0ffc0634b2f487
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/43869
Presubmit-Ready: Alexis Hétu <sugoi@google.com>
Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Chris Forbes <chrisforbes@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>