Compute clear colors where they'll be used.
Compute clear colors where they'll be used.

Change-Id: I54ee6018980088d8820e35483f4be7bbf974b7ef
Reviewed-on: https://swiftshader-review.googlesource.com/3260
Reviewed-by: Nicolas Capens <0612353e1fcebbfd4b302d9337447ca0cdfa9122@google.com>
Tested-by: Nicolas Capens <0612353e1fcebbfd4b302d9337447ca0cdfa9122@google.com>

bkaradzic/SwiftShader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,google/swiftshader,google/swiftshader,bkaradzic/SwiftShader,google/swiftshader