Make DOMImplementation::hasFeature() behave according to specification

LayoutTests/svg/W3C-SVG-1.1/struct-dom-03-b-expected.txt

Index: LayoutTests/svg/W3C-SVG-1.1/struct-dom-03-b-expected.txt
diff --git a/LayoutTests/svg/W3C-SVG-1.1/struct-dom-03-b-expected.txt b/LayoutTests/svg/W3C-SVG-1.1/struct-dom-03-b-expected.txt
index 9345e3082b413d9ee2c47427f2c704bd073a6f7b..ce382a9e7cfaae16946133960709bf63e1e6faca 100644
--- a/LayoutTests/svg/W3C-SVG-1.1/struct-dom-03-b-expected.txt
+++ b/LayoutTests/svg/W3C-SVG-1.1/struct-dom-03-b-expected.txt
@@ -10,9 +10,9 @@ layer at (0,0) size 480x360
     RenderSVGText {text} at (10,23) size 96x34 contains 1 chunk(s)
       RenderSVGInlineText {#text} at (0,0) size 96x34
         chunk 1 text run 1 at (10.00,50.00) startOffset 0 endOffset 8 width 96.00: "uievents"
-    RenderSVGText {text} at (370,23) size 54x34 contains 1 chunk(s)
-      RenderSVGInlineText {#text} at (0,0) size 54x34
-        chunk 1 text run 1 at (370.00,50.00) startOffset 0 endOffset 5 width 54.00: "false"
+    RenderSVGText {text} at (370,23) size 46x34 contains 1 chunk(s)
+      RenderSVGInlineText {#text} at (0,0) size 46x34
+        chunk 1 text run 1 at (370.00,50.00) startOffset 0 endOffset 4 width 46.00: "true"
     RenderSVGText {text} at (10,73) size 151x34 contains 1 chunk(s)
       RenderSVGInlineText {#text} at (0,0) size 151x34
         chunk 1 text run 1 at (10.00,100.00) startOffset 0 endOffset 11 width 151.00: "mouseevents"