shader: serialize resource plans for the shader cache

src/graphics/shader/recompiler/ir/ShaderIR.h

@@ -655,7 +655,6 @@ struct UniformFillPlan {
 // condition and fill values without translated blocks, plus reusable evaluation scratch.
 struct ResourcePlan {
 	struct SelectorKeys {
-		uint32_t              source = UINT32_MAX;
 		std::vector<uint32_t> values;
 		bool                  resolved = false;
 	};