compiler/types: Remove C++ static members for builtins
When we moved the bulk of glsl_type to C++, these globals were kept to avoid changes to compiler/glsl code in the MR. Now that landed, change the code to use the actual bultins directly.
When we moved the bulk of glsl_type to C++, these globals were kept to avoid changes to compiler/glsl code in the MR. Now that landed, change the code to use the actual bultins directly.