Remove meaningless uses of [TypeChecking=Nullable]

Source/core/svg/SVGPoint.idl

 /*
  * Copyright (C) 2004, 2005 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005 Rob Buis <buis@kde.org>
  * Copyright (C) 2006 Samuel Weinig <sam.weinig@gmail.com>
  * Copyright (C) 2006 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 [
     ImplementedAs=SVGPointTearOff,
     SetWrapperReferenceTo(SVGElement contextElement),
-    TypeChecking=Interface|Nullable,
+    TypeChecking=Interface,
 ] interface SVGPoint {
     [RaisesException=Setter] attribute float x;
     [RaisesException=Setter] attribute float y;
 
     [MeasureAs=SVGPointMatrixTransform] SVGPoint matrixTransform(SVGMatrix matrix);
 };