Move and rename RenderBR to LayoutBR.

LayoutTests/platform/win/tables/mozilla/bugs/bug51727-expected.txt

Index: LayoutTests/platform/win/tables/mozilla/bugs/bug51727-expected.txt
diff --git a/LayoutTests/platform/win/tables/mozilla/bugs/bug51727-expected.txt b/LayoutTests/platform/win/tables/mozilla/bugs/bug51727-expected.txt
index e2ad9597ce608b28caa2e78a92560e9e7405b162..d0fb055a55f8edf19fca8c5e8f5630ab96e80057 100644
--- a/LayoutTests/platform/win/tables/mozilla/bugs/bug51727-expected.txt
+++ b/LayoutTests/platform/win/tables/mozilla/bugs/bug51727-expected.txt
@@ -8,12 +8,12 @@ layer at (0,0) size 800x86
           RenderBlock (anonymous) at (8,3) size 151x16
             RenderText {#text} at (0,0) size 151x16
               text run at (0,0) width 151: "(1) Fill cell with long string"
-        RenderBR {BR} at (167,2) size 0x17
+        LayoutBR {BR} at (167,2) size 0x17
         RenderButton {INPUT} at (0,22) size 172x22 [bgcolor=#C0C0C0] [border: (2px outset #C0C0C0)]
           RenderBlock (anonymous) at (8,3) size 156x16
             RenderText {#text} at (0,0) size 156x16
               text run at (0,0) width 156: "(2) Fill cell with short string"
-        RenderBR {BR} at (172,24) size 0x17
+        LayoutBR {BR} at (172,24) size 0x17
       LayoutTable {TABLE} at (0,44) size 83x26
         LayoutTableSection {TBODY} at (0,0) size 83x26
           LayoutTableRow {TR} at (0,2) size 83x22