Revert "STENCIL_VALUE_UNKNOWN for DECR/INCR/INVERT"

This reverts commit 59d3b92e71.

Revert "zero alpha if stencil op consistently says to zero for format 5551 as well"

This reverts commit ed07a7f411.

GPU/GLES/FragmentShaderGenerator.cpp

@@ -149,15 +149,9 @@ StencilValueType ReplaceAlphaWithStencilType() {
 		case GE_STENCILOP_REPLACE:
 			return (gstate.getStencilTestRef() & 0x80) != 0 ? STENCIL_VALUE_ONE : STENCIL_VALUE_ZERO;
 
-		case GE_STENCILOP_ZERO:
-			if (gstate.getStencilOpZFail() == GE_STENCILOP_ZERO) {
-				return STENCIL_VALUE_ZERO;
-			} else {
-				return STENCIL_VALUE_KEEP;
-			}
-
 		// Decrementing always zeros, since there's only one bit.
 		case GE_STENCILOP_DECR:
+		case GE_STENCILOP_ZERO:
 			return STENCIL_VALUE_ZERO;
 
 		// Incrementing always fills, since there's only one bit.
@@ -186,11 +180,11 @@ StencilValueType ReplaceAlphaWithStencilType() {
 				return STENCIL_VALUE_KEEP;
 			}
 
+		// Decrementing always zeros, since there's only one bit.
 		case GE_STENCILOP_DECR:
 		case GE_STENCILOP_INCR:
 		case GE_STENCILOP_INVERT:
 			return STENCIL_VALUE_UNKNOWN;
-
 		case GE_STENCILOP_KEEP:
 			return STENCIL_VALUE_KEEP;
 		}