glsl: simplify resource list building code
This greatly simplifies the code to calculate if we should add a
buffer to the resource list. This uses the spec rules and simple
math to decide if we should add the buffer rather than complex
string processing.
This patch refines a patch present in the ARB_gl_spriv merge
request for the NIR linker and applies it to the GLSL IR linker.
This is why we also move the function to the shared linker code,
because we will want to reuse the code for the NIR linker also.
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>