Unnormalized texture coordinates are pretty much the same
as rectangle texture coordinates, with a few extra addressing
modes to support. ADDRESSING_CLAMP and ADDRESSING_BORDER
work properly. Other modes can't used with unnormalized
texture coordinates, according to the Vulkan spec:
"If unnormalizedCoordinates is VK_TRUE,
 addressModeU and addressModeV must each be either
 VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE or
 VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER"

Bug b/129523279

Change-Id: I3e39c16172bc5825ec48c6395f52e9b177df1304
Tests: dEQP-VK.texture.filtering.unnormal.*
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/31648Tested-by: Alexis Hétu <sugoi@google.com>
Presubmit-Ready: Alexis Hétu <sugoi@google.com>
Reviewed-by: Chris Forbes <chrisforbes@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>