Convert fast/multicol/margin-collapse to reftest.

LayoutTests/platform/win/fast/multicol/margin-collapse-expected.txt

Index: LayoutTests/platform/win/fast/multicol/margin-collapse-expected.txt
diff --git a/LayoutTests/platform/win/fast/multicol/margin-collapse-expected.txt b/LayoutTests/platform/win/fast/multicol/margin-collapse-expected.txt
deleted file mode 100644
index b73d9fd1c518c1b4e69f5baaa1337c36bc7a2cd9..0000000000000000000000000000000000000000
--- a/LayoutTests/platform/win/fast/multicol/margin-collapse-expected.txt
+++ /dev/null
@@ -1,14 +0,0 @@
-layer at (0,0) size 800x600
-  RenderView at (0,0) size 800x600
-layer at (0,0) size 800x600
-  RenderBlock {HTML} at (0,0) size 800x600
-    RenderBody {BODY} at (8,8) size 784x584
-      RenderBlock (anonymous) at (0,0) size 784x36
-        RenderText {#text} at (0,0) size 784x35
-          text run at (0,0) width 489: "The two purple rectangles below should both be at the top of their columns. "
-          text run at (488,0) width 296: "If one is lower than the other, than the test has"
-          text run at (0,18) width 41: "failed."
-layer at (8,44) size 784x304
-  RenderBlock {DIV} at (0,36) size 784x304 [border: (2px solid #000000)]
-    RenderBlock {DIV} at (2,2) size 382x200 [bgcolor=#800080]
-    RenderBlock {DIV} at (2,302) size 382x200 [bgcolor=#800080]