Migrate svg layout tests to use slimming paint by default

LayoutTests/svg/repaint/mask-clip-target-transform-expected.txt

 {
   "bounds": [800, 600],
   "children": [
     {
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "repaintRects": [
         [150, 100, 100, 50],
         [100, 150, 50, 100],
         [100, 0, 200, 300],
         [100, 0, 200, 300],
         [50, 150, 100, 100],
         [0, 100, 300, 200],
         [0, 0, 300, 100]
+      ],
+      "paintInvalidationClients": [
+        "LayoutSVGContainer g",
+        "LayoutSVGRect rect id='masker'",
+        "LayoutSVGContainer g",
+        "LayoutSVGRect rect id='clipper'"
       ]
     }
   ]
 }