Implement stencil action 2 in SW renderer

src/video_core/pica.h

@@ -431,6 +431,7 @@ struct Regs {
 
     enum class StencilAction : u32 {
         Keep = 0,
+        AndReverse = 2,
         Xor  = 5,
     };
 

src/video_core/rasterizer.cpp

@@ -221,6 +221,9 @@ static u8 PerformStencilAction(Regs::StencilAction action, u8 dest, u8 ref) {
     case Regs::StencilAction::Keep:
         return dest;
 
+    case Regs::StencilAction::AndReverse:
+        return dest & ~ref;
+
     case Regs::StencilAction::Xor:
         return dest ^ ref;