Rework XmlUtilTest to avoid relying on internal JDK classes

DEVSIX-6628

Author: Eugene Bochilo

io/src/test/java/com/itextpdf/io/util/XmlUtilTest.java

@@ -44,8 +44,6 @@ This file is part of the iText (R) project.
 
 import com.itextpdf.test.ExtendedITextTest;
 import com.itextpdf.test.annotations.type.UnitTest;
-import com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderFactoryImpl;
-import com.sun.org.apache.xerces.internal.jaxp.SAXParserFactoryImpl;
 import org.junit.Assert;
 import org.junit.Test;
 import org.junit.experimental.categories.Category;
@@ -67,13 +65,13 @@ public void initNewXmlDocumentTest() throws Exception {
     public void getDocumentBuilderFactoryTest() {
         DocumentBuilderFactory factory = XmlUtil.getDocumentBuilderFactory();
 
-        Assert.assertEquals(DocumentBuilderFactoryImpl.class, factory.getClass());
+        Assert.assertEquals(DocumentBuilderFactory.newInstance().getClass(), factory.getClass());
     }
 
     @Test
     public void createSAXParserFactoryTest() {
         SAXParserFactory factory = XmlUtil.createSAXParserFactory();
 
-        Assert.assertEquals(SAXParserFactoryImpl.class, factory.getClass());
+        Assert.assertEquals(SAXParserFactory.newInstance().getClass(), factory.getClass());
     }
 }