Remove memory allocations in some hot paths

src/shader_recompiler/runtime_info.h

@@ -84,7 +84,8 @@ struct RuntimeInfo {
     bool glasm_use_storage_buffers{};
 
     /// Transform feedback state for each varying
-    std::vector<TransformFeedbackVarying> xfb_varyings;
+    std::array<TransformFeedbackVarying, 256> xfb_varyings{};
+    u32 xfb_count{0};
 };
 
 } // namespace Shader