Move and rename RenderBR to LayoutBR.

LayoutTests/platform/mac/tables/mozilla/bugs/bug8950-expected.txt

Index: LayoutTests/platform/mac/tables/mozilla/bugs/bug8950-expected.txt
diff --git a/LayoutTests/platform/mac/tables/mozilla/bugs/bug8950-expected.txt b/LayoutTests/platform/mac/tables/mozilla/bugs/bug8950-expected.txt
index 3fffaa3b6611a66f7b605836610053f4227ce53e..b807aef129e153920aeb42943570593af8711cd7 100644
--- a/LayoutTests/platform/mac/tables/mozilla/bugs/bug8950-expected.txt
+++ b/LayoutTests/platform/mac/tables/mozilla/bugs/bug8950-expected.txt
@@ -75,11 +75,11 @@ layer at (0,0) size 800x600
                                                           RenderText {#text} at (2,2) size 58x18
                                                             text run at (2,2) width 58: "Cartoons"
       RenderBlock (anonymous) at (0,233) size 784x18
-        RenderBR {BR} at (0,0) size 0x18
+        LayoutBR {BR} at (0,0) size 0x18
       RenderBlock {P} at (0,267) size 784x54
         RenderText {#text} at (0,0) size 561x18
           text run at (0,0) width 561: "The second (nested) table below has fixed widths 300px, 500px, 200px (outer to inner)."
-        RenderBR {BR} at (560,14) size 1x0
+        LayoutBR {BR} at (560,14) size 1x0
         RenderText {#text} at (0,18) size 66x18
           text run at (0,18) width 66: "When the "
         RenderInline {CODE} at (0,0) size 56x15
@@ -92,7 +92,7 @@ layer at (0,0) size 800x600
             text run at (238,20) width 102: "'onMouseOver'"
         RenderText {#text} at (339,18) size 217x18
           text run at (339,18) width 217: ", the outer table reflows to 300px,"
-        RenderBR {BR} at (555,32) size 1x0
+        LayoutBR {BR} at (555,32) size 1x0
         RenderText {#text} at (0,36) size 311x18
           text run at (0,36) width 311: "clipping the middle (500px) table in the process."
       LayoutTable {TABLE} at (0,337) size 300x28 [border: (1px outset #808080)]
@@ -102,7 +102,7 @@ layer at (0,0) size 800x600
               RenderText {#text} at (2,2) size 177x18
                 text run at (2,2) width 177: "300px wide for comparison"
       RenderBlock (anonymous) at (0,365) size 784x18
-        RenderBR {BR} at (0,0) size 0x18
+        LayoutBR {BR} at (0,0) size 0x18
       LayoutTable {TABLE} at (0,383) size 510x48 [border: (1px outset #808080)]
         LayoutTableSection {TBODY} at (1,1) size 508x46
           LayoutTableRow {TR} at (0,2) size 508x42