Allows "merging" render targets that overlap on the Y access. Fixes #7295 (Juiced 2)

To be safe, gating this behind the related AllowLargeFBTextureOffsets,
which is also required for the effect to work.

Additionally, fixes the offset check for X offsets, which I guess is a
very small risk.

GPU/Common/GPUStateUtils.cpp

@@ -584,6 +584,7 @@ void ConvertViewportAndScissor(bool useBufferedRendering, float renderWidth, flo
 	}
 
 	renderX = gstate_c.curRTOffsetX;
+	renderY = gstate_c.curRTOffsetY;
 
 	// Scissor
 	int scissorX1 = gstate.getScissorX1();