A couple of ref-test tweaks in preparation of Skia changes

LayoutTests/fast/canvas/canvas-createImageBitmap-colorClamping-expected.html

Index: LayoutTests/fast/canvas/canvas-createImageBitmap-colorClamping-expected.html
diff --git a/LayoutTests/fast/canvas/canvas-createImageBitmap-colorClamping-expected.html b/LayoutTests/fast/canvas/canvas-createImageBitmap-colorClamping-expected.html
index d5b60a2f8d8d77d3b70868644dd89ac31e300410..b9356d3571b3eb874cfe53ce34820fee78f6d8fc 100644
--- a/LayoutTests/fast/canvas/canvas-createImageBitmap-colorClamping-expected.html
+++ b/LayoutTests/fast/canvas/canvas-createImageBitmap-colorClamping-expected.html
@@ -9,7 +9,14 @@ var ctx = canvas.getContext("2d");
 
 ctx.fillStyle = 'green';
 ctx.fillRect(0, 0, 100, 100);
-ctx.fillRect(120, 0, 150, 150);
+
+ctx.save();
+ctx.beginPath();
+ctx.rect(120, 0, 150, 150);
+ctx.clip();
+ctx.fillRect(0, 0, 250, 200);
+ctx.restore();
+
 </script>
 <p>Two green squares with no color bleeding should be visible.</p>
 </body>