Add support for Vertex Program A and other small shader improvements (#192)

* Add WIP support for Vertex Program A, add the FADD_I32 shader instruction, small fix on FFMA_I encoding, nits

* Add separate subroutines for program A/B, and copy attributes to a temp

* Move finalization code to main

* Add new line after flip uniform on the shader

* Handle possible case where VPB uses an output attribute written by VPA but not available on the vbo

* Address PR feedback

Ryujinx.Graphics/Gal/ShaderDeclInfo.cs

@@ -23,13 +23,5 @@ namespace Ryujinx.Graphics.Gal
                 Size = NewSize;
             }
         }
-
-        internal void SetCbufOffs(int Offs)
-        {
-            if (Index < Offs)
-            {
-                Index = Offs;
-            }
-        }
     }
 }