Bold and Italic style get stuck when applied on a selection having content with mixed editability

LayoutTests/editing/editing.js

 //-------------------------------------------------------------------------------------------------------
 // Java script library to run editing layout tests
 
 var commandCount = 1;
 var commandDelay = window.location.search.substring(1);
 if (commandDelay == '')
     commandDelay = 0;
 var selection = window.getSelection();
 
 //-------------------------------------------------------------------------------------------------------
@@ skipping 886 matching lines @@
     if (window.testRunner)
         testRunner.dumpEditingCallbacks();
 
     var elem = document.getElementById("test");
     var selection = window.getSelection();
     selection.setPosition(elem, 0);
     editingTest();
 }
 
 var dumpAsText = false;
-var markupResultList = document.createElement('ol');
+var elementsForDumpingMarkupList = [document.createElement('ol')];
 
 function runDumpAsTextEditingTest(enableCallbacks) {
     if (window.testRunner) {
          testRunner.dumpAsText();
          if (enableCallbacks)
             testRunner.dumpEditingCallbacks();
      }
 
     dumpAsText = true;
 
     var elem = document.getElementById("test");
     var selection = window.getSelection();
     selection.setPosition(elem, 0);
     editingTest();
 
-    document.body.appendChild(markupResultList);
+    for (var i = 0; i < elementsForDumpingMarkupList.length; i++)
+        document.body.appendChild(elementsForDumpingMarkupList[i]);
 }
 
 function debugForDumpAsText(name) {
     if (dumpAsText && document.getElementById("root")) {
         var newItem = document.createElement('li');
         newItem.appendChild(document.createTextNode(name+": "+document.getElementById("root").innerHTML));
-        markupResultList.appendChild(newItem);
+        elementsForDumpingMarkupList[elementsForDumpingMarkupList.length - 1].appendChild(newItem);
     }
 }
 
+function startNewMarkupGroup(label) {
+    if (!elementsForDumpingMarkupList[elementsForDumpingMarkupList.length - 1].hasChildNodes())
+        elementsForDumpingMarkupList.pop();
+    elementsForDumpingMarkupList.push(document.createElement('br'));
+    elementsForDumpingMarkupList.push(document.createTextNode(label));
+    elementsForDumpingMarkupList.push(document.createElement('ol'));
+}
+
 //-------------------------------------------------------------------------------------------------------
 
 
 function execBackColorCommand() {
     document.execCommand("BackColor", false, "Chartreuse");
     debugForDumpAsText('execBackColorCommand');
 }
 function backColorCommand() {
     if (commandDelay > 0) {
         queueCommand(execBackColorCommand, commandCount * commandDelay);
@@ skipping 27 matching lines @@
 function executeCommand(command,arg1,arg2) {
     if (commandDelay > 0) {
         queueCommand(runCommand, commandCount * commandDelay);
         commandCount++;
     }
     else {
         runCommand(command,arg1,arg2);
     }
 }