Rewrite fast/multicol/shadow-breaking.html as a check-layout test.

LayoutTests/platform/mac/fast/multicol/shadow-breaking-expected.txt

Index: LayoutTests/platform/mac/fast/multicol/shadow-breaking-expected.txt
diff --git a/LayoutTests/platform/mac/fast/multicol/shadow-breaking-expected.txt b/LayoutTests/platform/mac/fast/multicol/shadow-breaking-expected.txt
deleted file mode 100644
index 182d54b4716ddf8d2ca34cfdff57783278d96ce9..0000000000000000000000000000000000000000
--- a/LayoutTests/platform/mac/fast/multicol/shadow-breaking-expected.txt
+++ /dev/null
@@ -1,38 +0,0 @@
-layer at (0,0) size 800x600
-  RenderView at (0,0) size 800x600
-layer at (0,0) size 800x8
-  RenderBlock {HTML} at (0,0) size 800x8
-    RenderBody {BODY} at (8,8) size 784x0
-      RenderBlock {DIV} at (0,0) size 784x0
-layer at (20,36) size 424x270
-  RenderBlock (positioned) {P} at (20,36) size 424x270 [border: (2px solid #000000)]
-    RenderBlock (floating) {<pseudo:first-letter>} at (2,2) size 24x41
-      RenderTextFragment at (0,0) size 25x41
-        text run at (0,0) width 25: "L"
-    RenderTextFragment {#text} at (30,2) size 200x491
-      text run at (30,2) width 172: "orem ipsum dolor sit"
-      text run at (30,20) width 172: "amet, consectetur"
-      text run at (2,38) width 200: "adipiscing elit. Cras pharetra"
-      text run at (2,56) width 200: "mollis pharetra. Suspendisse"
-      text run at (2,74) width 200: "lacinia orci et felis tristique"
-      text run at (2,92) width 200: "sit amet semper massa"
-      text run at (2,110) width 200: "tempus. Suspendisse"
-      text run at (2,128) width 200: "consectetur tempor pulvinar."
-      text run at (2,146) width 200: "Proin dui eros, ultricies vel"
-      text run at (2,164) width 200: "malesuada vel, tempor at"
-      text run at (2,182) width 200: "ante. Nam eget nisl dui."
-      text run at (2,200) width 200: "Donec molestie lectus a nunc"
-      text run at (2,218) width 200: "scelerisque blandit. Nam non"
-      text run at (2,236) width 200: "ligula massa, sed suscipit"
-      text run at (2,277) width 200: "turpis. Etiam eget ligula sit"
-      text run at (2,295) width 200: "amet turpis venenatis dictum"
-      text run at (2,313) width 200: "in eleifend augue. Duis tellus"
-      text run at (2,331) width 200: "lectus, volutpat et adipiscing"
-      text run at (2,349) width 200: "a, pellentesque eu metus."
-      text run at (2,367) width 200: "Aenean suscipit congue"
-      text run at (2,385) width 200: "mauris at gravida. Integer"
-      text run at (2,403) width 200: "lectus ligula, consectetur sit"
-      text run at (2,421) width 200: "amet venenatis id,"
-      text run at (2,439) width 200: "scelerisque eget nisl. Nunc"
-      text run at (2,457) width 200: "dapibus posuere risus, vitae"
-      text run at (2,475) width 153: "tempor nibh iaculis et."