Move the remaining rendering/svg/RenderSVG* files to layout.

LayoutTests/svg/custom/grayscale-gradient-mask-expected.txt

Index: LayoutTests/svg/custom/grayscale-gradient-mask-expected.txt
diff --git a/LayoutTests/svg/custom/grayscale-gradient-mask-expected.txt b/LayoutTests/svg/custom/grayscale-gradient-mask-expected.txt
index 8607c7efa24ee25f35acffc42f7202d166642af7..17f161d20f23ce247fb5008ba55067a0f08175aa 100644
--- a/LayoutTests/svg/custom/grayscale-gradient-mask-expected.txt
+++ b/LayoutTests/svg/custom/grayscale-gradient-mask-expected.txt
@@ -1,11 +1,11 @@
 layer at (0,0) size 800x600
   RenderView at (0,0) size 800x600
 layer at (0,0) size 800x600
-  RenderSVGRoot {svg} at (0,143) size 781x294
+  LayoutSVGRoot {svg} at (0,143) size 781x294
     LayoutSVGHiddenContainer {defs} at (0,0) size 0x0
       LayoutSVGResourceLinearGradient {linearGradient} [id="Gradient"] [gradientUnits=userSpaceOnUse] [start=(0,0)] [end=(800,0)]
-        RenderSVGGradientStop {stop} [offset=0.00] [color=#FFFFFF]
-        RenderSVGGradientStop {stop} [offset=1.00] [color=#000000]
+        LayoutSVGGradientStop {stop} [offset=0.00] [color=#FFFFFF]
+        LayoutSVGGradientStop {stop} [offset=1.00] [color=#000000]
     LayoutSVGResourceMasker {mask} [id="Mask"] [maskUnits=userSpaceOnUse] [maskContentUnits=userSpaceOnUse]
       LayoutSVGRect {rect} at (0,143) size 781x294 [fill={[type=LINEAR-GRADIENT] [id="Gradient"]}] [x=0.00] [y=0.00] [width=800.00] [height=300.00]
     LayoutSVGRect {rect} at (0,143) size 781x294 [fill={[type=SOLID] [color=#FF8080]}] [x=0.00] [y=0.00] [width=800.00] [height=300.00]