Move and rename RenderBR to LayoutBR.

LayoutTests/platform/win/fast/dom/HTMLTableElement/colSpan-expected.txt

 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 {P} at (0,0) size 784x18
         RenderText {#text} at (0,0) size 172x17
           text run at (0,0) width 172: "Tests: the colspan attribute"
-        RenderBR {BR} at (171,14) size 1x0
+        LayoutBR {BR} at (171,14) size 1x0
       RenderBlock {P} at (0,34) size 784x72
         RenderText {#text} at (0,0) size 75x17
           text run at (0,0) width 75: "Conditions:"
-        RenderBR {BR} at (74,14) size 1x0
+        LayoutBR {BR} at (74,14) size 1x0
         RenderText {#text} at (0,18) size 763x53
           text run at (0,18) width 668: "The colSpan attribute specifies the number of columns spanned by the current cell. The default value of "
           text run at (667,18) width 96: "this attribute is"
           text run at (0,36) width 551: "one (\"1\"). The value zero (\"0\") means that the cell spans all columns from the current "
           text run at (550,36) width 208: "column to the last column of the"
           text run at (0,54) width 372: "column group (COLGROUP) in which the cell is defined."
       RenderBlock {P} at (0,122) size 784x54
         RenderText {#text} at (0,0) size 776x53
           text run at (0,0) width 776: "The first table tests the default value of one, and an input of 7, which is within the normal range of expect input. The first"
           text run at (0,18) width 722: "column in the first row should span only column \"one\" and the second cell should span all of the other columns. "
           text run at (721,18) width 26: "The"
           text run at (0,36) width 572: "second table tests the zero value. \"Just A\" should span \"A\" and \"Just B\" should span \"B.\""
       RenderBlock {HR} at (0,192) size 784x2 [border: (1px inset #EEEEEE)]
       RenderBlock (anonymous) at (0,202) size 784x18
-        RenderBR {BR} at (0,0) size 0x17
+        LayoutBR {BR} at (0,0) size 0x17
       LayoutTable {TABLE} at (0,220) size 278x70 [border: (1px outset #808080)]
         RenderBlock {CAPTION} at (0,0) size 278x18
           RenderText {#text} at (29,0) size 220x17
             text run at (29,0) width 220: "Testing Default and Regular Input"
         LayoutTableSection {TBODY} at (1,19) size 276x50
           LayoutTableRow {TR} at (0,2) size 276x22
             LayoutTableCell {TD} at (2,2) size 34x22 [border: (1px inset #808080)] [r=0 c=0 rs=1 cs=1]
               RenderText {#text} at (2,2) size 30x17
                 text run at (2,2) width 30: "First"
             LayoutTableCell {TD} at (38,2) size 236x22 [border: (1px inset #808080)] [r=0 c=1 rs=1 cs=7]
@@ skipping 18 matching lines @@
             LayoutTableCell {TD} at (170,26) size 23x22 [border: (1px inset #808080)] [r=1 c=5 rs=1 cs=1]
               RenderText {#text} at (2,2) size 19x17
                 text run at (2,2) width 19: "six"
             LayoutTableCell {TD} at (195,26) size 41x22 [border: (1px inset #808080)] [r=1 c=6 rs=1 cs=1]
               RenderText {#text} at (2,2) size 37x17
                 text run at (2,2) width 37: "seven"
             LayoutTableCell {TD} at (238,26) size 36x22 [border: (1px inset #808080)] [r=1 c=7 rs=1 cs=1]
               RenderText {#text} at (2,2) size 32x17
                 text run at (2,2) width 32: "eight"
       RenderBlock (anonymous) at (0,290) size 784x18
-        RenderBR {BR} at (0,0) size 0x17
+        LayoutBR {BR} at (0,0) size 0x17
       LayoutTable {TABLE} at (0,308) size 199x70 [border: (1px outset #808080)]
         RenderBlock {CAPTION} at (0,0) size 199x18
           RenderText {#text} at (15,0) size 169x17
             text run at (15,0) width 169: "Testing Zero Special Case"
         LayoutTableSection {TBODY} at (1,19) size 197x50
           LayoutTableRow {TR} at (0,2) size 197x22
             LayoutTableCell {TD} at (2,2) size 45x22 [border: (1px inset #808080)] [r=0 c=0 rs=1 cs=1]
               RenderText {#text} at (2,2) size 41x17
                 text run at (2,2) width 41: "Just A"
             LayoutTableCell {TD} at (49,2) size 44x22 [border: (1px inset #808080)] [r=0 c=1 rs=1 cs=1]
@@ skipping 17 matching lines @@
                 text run at (2,2) width 10: "E"
             LayoutTableCell {TD} at (146,26) size 13x22 [border: (1px inset #808080)] [r=1 c=5 rs=1 cs=1]
               RenderText {#text} at (2,2) size 9x17
                 text run at (2,2) width 9: "F"
             LayoutTableCell {TD} at (161,26) size 16x22 [border: (1px inset #808080)] [r=1 c=6 rs=1 cs=1]
               RenderText {#text} at (2,2) size 12x17
                 text run at (2,2) width 12: "G"
             LayoutTableCell {TD} at (179,26) size 16x22 [border: (1px inset #808080)] [r=1 c=7 rs=1 cs=1]
               RenderText {#text} at (2,2) size 12x17
                 text run at (2,2) width 12: "H"