SPIRV-Tools' pass to do this is incomplete, and implementing the
remaining pieces as a SPIRV->SPIRV transform is more work than
implementing them here.

Related SPIRV-Tools issues: 2585 2586

Bug: b/127454276
Test: dEQP-VK.*quantize*
Change-Id: I892de80dff366fb3bc417315b5db15d850577c47
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/31348Tested-by: Chris Forbes <chrisforbes@google.com>
Presubmit-Ready: Chris Forbes <chrisforbes@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>