Simplifies things throughout the cpp.

Bug: b/128539387
Change-Id: I7abbe4731d82877204976d654859cba88d1a3047
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/26531Tested-by: Ben Clayton <headlessclayton@gmail.com>
Reviewed-by: Chris Forbes <chrisforbes@google.com>