Rewrite svg/dynamic-updates to use text-based repaint harness

LayoutTests/svg/animations/resources/SVGTestCase.js

 // Force activating pixel tests - this variable is used in resources/js-test.js, when calling setDumpAsText().
 window.enablePixelTesting = true;
 
 var svgNS = "http://www.w3.org/2000/svg";
 var xlinkNS = "http://www.w3.org/1999/xlink";
 var xhtmlNS = "http://www.w3.org/1999/xhtml";
 
 var rootSVGElement;
 var iframeElement;
 
@@ skipping 46 matching lines @@
     if (window.eventSender) {
         eventSender.mouseMoveTo(x, y);
         eventSender.mouseDown();
         eventSender.mouseUp();
     }
 }
 
 function completeTest() {
     finishJSTest();
 }