Fix restrictions on squashing with incompatible scroll.

LayoutTests/compositing/squashing/squash-above-fixed-2-expected.txt

Index: LayoutTests/compositing/squashing/squash-above-fixed-2-expected.txt
diff --git a/LayoutTests/compositing/squashing/squash-above-fixed-2-expected.txt b/LayoutTests/compositing/squashing/squash-above-fixed-2-expected.txt
index 6651a7be9855263bb74021524d4bc0a257e0d84c..a3a597f9d165f4d236bbe71b3740f40fbb46116b 100644
--- a/LayoutTests/compositing/squashing/squash-above-fixed-2-expected.txt
+++ b/LayoutTests/compositing/squashing/squash-above-fixed-2-expected.txt
@@ -8,7 +8,7 @@ CASE 1, original layer tree:
       (bounds 785.00 4050.00)
       (contentsOpaque 1)
       (drawsContent 1)
-      (children 2
+      (children 1
         (GraphicsLayer
           (bounds 400.00 200.00)
           (contentsOpaque 1)
@@ -16,20 +16,22 @@ CASE 1, original layer tree:
           (backgroundColor #0000FF)
           (children 1
             (GraphicsLayer
-              (bounds 50.00 50.00)
-              (contentsOpaque 1)
-              (drawsContent 1)
-              (backgroundColor #FF0000)
+              (children 2
+                (GraphicsLayer
+                  (bounds 50.00 50.00)
+                  (contentsOpaque 1)
+                  (drawsContent 1)
+                  (backgroundColor #FF0000)
+                )
+                (GraphicsLayer
+                  (position 100.00 50.00)
+                  (bounds 200.00 4000.00)
+                  (drawsContent 1)
+                )
+              )
             )
           )
         )
-        (GraphicsLayer
-          (position 100.00 50.00)
-          (bounds 200.00 4000.00)
-          (contentsOpaque 1)
-          (drawsContent 1)
-          (backgroundColor #00FFFF)
-        )
       )
     )
   )
@@ -42,7 +44,7 @@ CASE 2, scrolling y to 80, the "container" element should remain positioned with
       (bounds 785.00 4050.00)
       (contentsOpaque 1)
       (drawsContent 1)
-      (children 2
+      (children 1
         (GraphicsLayer
           (position 0.00 80.00)
           (bounds 400.00 200.00)
@@ -51,20 +53,22 @@ CASE 2, scrolling y to 80, the "container" element should remain positioned with
           (backgroundColor #0000FF)
           (children 1
             (GraphicsLayer
-              (bounds 50.00 50.00)
-              (contentsOpaque 1)
-              (drawsContent 1)
-              (backgroundColor #FF0000)
+              (children 2
+                (GraphicsLayer
+                  (bounds 50.00 50.00)
+                  (contentsOpaque 1)
+                  (drawsContent 1)
+                  (backgroundColor #FF0000)
+                )
+                (GraphicsLayer
+                  (position 100.00 -30.00)
+                  (bounds 200.00 4000.00)
+                  (drawsContent 1)
+                )
+              )
             )
           )
         )
-        (GraphicsLayer
-          (position 100.00 50.00)
-          (bounds 200.00 4000.00)
-          (contentsOpaque 1)
-          (drawsContent 1)
-          (backgroundColor #00FFFF)
-        )
       )
     )
   )