This complements the const-cache in 34348.

Timings for the Glass demo running on a i7-4930K:

this change:               24.25 FPS
this change without 34528: 23.02 FPS
parent change (inc 34528): 22.46 FPS

Bug: b/137649247
Change-Id: I206cdaabfaf63da7f67e3cd5f6823f3343b823c8
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/34528Tested-by: Ben Clayton <bclayton@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>