Add a number of tests for layer squashing

LayoutTests/compositing/squashing/squash-onto-transform-backing-expected.txt

Index: LayoutTests/compositing/squashing/squash-onto-transform-backing-expected.txt
diff --git a/LayoutTests/css3/compositing/mix-blend-mode-isolation-remove-expected.txt b/LayoutTests/compositing/squashing/squash-onto-transform-backing-expected.txt
similarity index 57%
copy from LayoutTests/css3/compositing/mix-blend-mode-isolation-remove-expected.txt
copy to LayoutTests/compositing/squashing/squash-onto-transform-backing-expected.txt
index 68babb78aae0ff4ac96ca51db3e1a499c53e39e6..bfef320bbfd753e906e950db0729bc6dff148abc 100644
--- a/LayoutTests/css3/compositing/mix-blend-mode-isolation-remove-expected.txt
+++ b/LayoutTests/compositing/squashing/squash-onto-transform-backing-expected.txt
@@ -7,21 +7,17 @@
       (drawsContent 1)
       (children 1
         (GraphicsLayer
-          (position 8.00 8.00)
-          (bounds 784.00 90.00)
-          (isolate 1)
-          (contentsOpaque 1)
           (children 2
             (GraphicsLayer
-              (bounds 784.00 90.00)
+              (position 100.00 100.00)
+              (bounds 100.00 100.00)
               (contentsOpaque 1)
-              (drawsContent 1)
-              (backfaceVisibility hidden)
-              (backgroundColor #008000)
+              (transform [0.71 0.71 0.00 0.00] [-0.71 0.71 0.00 0.00] [0.00 0.00 1.00 0.00] [0.00 0.00 0.00 1.00])
             )
             (GraphicsLayer
-              (bounds 160.00 90.00)
-              (blendMode multiply)
+              (position 20.00 20.00)
+              (bounds 260.00 260.00)
+              (drawsContent 1)
             )
           )
         )