Get rid of multiple inheritence for SVGViewElement interface

LayoutTests/svg/custom/global-constructors-expected.txt

Index: LayoutTests/svg/custom/global-constructors-expected.txt
diff --git a/LayoutTests/svg/custom/global-constructors-expected.txt b/LayoutTests/svg/custom/global-constructors-expected.txt
index 99532f4951de8b51c032656829e924bf1e6f3731..147647d0a2a6d28ccedd8f493204b12b01083735 100644
--- a/LayoutTests/svg/custom/global-constructors-expected.txt
+++ b/LayoutTests/svg/custom/global-constructors-expected.txt
@@ -28,9 +28,6 @@ FAIL SVGLocatable.toString() should be function SVGLocatable() { [native code] }
 FAIL SVGTransformable.toString() should be function SVGTransformable() { [native code] }. Threw exception ReferenceError: SVGTransformable is not defined
 FAIL SVGTests.toString() should be function SVGTests() { [native code] }. Threw exception ReferenceError: SVGTests is not defined
 FAIL SVGLangSpace.toString() should be function SVGLangSpace() { [native code] }. Threw exception ReferenceError: SVGLangSpace is not defined
-FAIL SVGExternalResourcesRequired.toString() should be function SVGExternalResourcesRequired() { [native code] }. Threw exception ReferenceError: SVGExternalResourcesRequired is not defined
-FAIL SVGFitToViewBox.toString() should be function SVGFitToViewBox() { [native code] }. Threw exception ReferenceError: SVGFitToViewBox is not defined
-PASS SVGZoomAndPan.toString() is 'function SVGZoomAndPan() { [native code] }'
 PASS SVGViewSpec.toString() is 'function SVGViewSpec() { [native code] }'
 FAIL SVGURIReference.toString() should be function SVGURIReference() { [native code] }. Threw exception ReferenceError: SVGURIReference is not defined
 FAIL SVGCSSRule.toString() should be function SVGCSSRule() { [native code] }. Threw exception ReferenceError: SVGCSSRule is not defined