Remove deprecated window.showModalDialog()

LayoutTests/fast/dom/resources/wrapper-identity-base.js

 // We use a static list of window properties to avoid breaking when new properties are added.
 var staticWindowProperties = [
     'CSSPrimitiveValue',
     'CSSRule',
     'CSSStyleDeclaration',
     'CSSValue',
     'CSSCharsetRule',
     'CSSImportRule',
     'CSSMediaRule',
     'CSSFontFaceRule',
@@ skipping 140 matching lines @@
     'resizeBy',
     'resizeTo',
     'screen',
     'scroll',
     'scrollBy',
     'scrollTo',
     'scrollbars',
     'self',
     'setInterval',
     'setTimeout',
-    'showModalDialog',
     'status',
     'statusbar',
     'stop',
     'test',
     'toolbar',
     'top',
     'window'
 ];
 
 
 function isEqualJS(a, b)
 {
     return a === b;
 }
 
 function isEqualObjC(a, b)
 {
     return Boolean(objCController.identityIsEqual(a, b));
 }
 
 function testJS(s)
 {
     shouldBeTrue("var object = " + s + "; isEqualJS(object, object);");
 }
 
 function testObjC(s)
 {
     shouldBeTrue("var object = " + s + "; isEqualObjC(object, object);");
 }