Handling new opcodes in PixelProgram and VertexProgram

The new opcodes related to true int and uint support in
glsl shader are now handled properly in PixelProgram and
VertexProgram.

Change-Id: I62565844f24708b4bd89dd99bbf971b55495c5da
Reviewed-on: https://swiftshader-review.googlesource.com/3932
Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>