We had these already for UInt4.

Bug: b/139010488
Change-Id: Idb9451db1221da7b309b64ef407abcea33fea21e
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/34768
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Ben Clayton <bclayton@google.com>