Scaling and offset fix for FELighting (software and skia paths)

LayoutTests/svg/dynamic-updates/script-tests/SVGFESpotLightElement-dom-pointsAtZ-attr.js

 // [Name] SVGFESpotLightElement-dom-pointsAtZ-attr.js
 // [Expected rendering result] A shining cone (performed by diffuse lighting) - and a series of PASS messages
 
 description("Tests dynamic updates of the 'pointsAtZ' attribute of the SVGFESpotLightElement object")
 createSVGTestCase();
 
 var spotLightElement = createSVGElement("feSpotLight");
-spotLightElement.setAttribute("x", "113");
-spotLightElement.setAttribute("y", "0");
+spotLightElement.setAttribute("x", "83");
+spotLightElement.setAttribute("y", "-30");
 spotLightElement.setAttribute("z", "100");
-spotLightElement.setAttribute("pointsAtX", "113");
-spotLightElement.setAttribute("pointsAtY", "100");
+spotLightElement.setAttribute("pointsAtX", "83");
+spotLightElement.setAttribute("pointsAtY", "70");
 spotLightElement.setAttribute("pointsAtZ", "100");
 spotLightElement.setAttribute("specularExponent", "1");
 spotLightElement.setAttribute("limitingConeAngle", "15");
 
 var gradientElement = createSVGElement("feDiffuseLighting");
 gradientElement.setAttribute("surfaceScale", "1");
 gradientElement.setAttribute("diffuseConstant", "1");
 gradientElement.setAttribute("lighting-color", "aqua");
 gradientElement.appendChild(spotLightElement);
 
@@ skipping 19 matching lines @@
 
 function repaintTest() {
     spotLightElement.setAttribute("pointsAtZ", "0");
     shouldBeEqualToString("spotLightElement.getAttribute('pointsAtZ')", "0");
 
     completeTest();
 }
 
 
 var successfullyParsed = true;