Revert #6192. It was causing a JS error on devstack.

TNL-1070

cms/static/sass/elements/_modal-window.scss

@@ -222,10 +222,6 @@
       height: 365px;
     }
 
-    .CodeMirror-advanced {
-      height: 435px;
-    }
-
     .wrapper-comp-settings {
 
       .list-input {

common/lib/xmodule/xmodule/js/src/combinedopenended/edit.coffee

@@ -62,7 +62,6 @@ Write a persuasive essay to a newspaper reflecting your views on censorship in l
       $(@element.find('.xml-box')).hide()
     else
       @createXMLEditor()
-      @xml_editor.display.wrapper.className += " CodeMirror-advanced";
 
     @alertTaskRubricModification()
 
@@ -93,7 +92,6 @@ Write a persuasive essay to a newspaper reflecting your views on censorship in l
       @toggleCheatsheetVisibility()
     if @confirmConversionToXml()
       @createXMLEditor(OpenEndedMarkdownEditingDescriptor.markdownToXml(@markdown_editor.getValue()))
-      @xml_editor.display.wrapper.className += " CodeMirror-advanced";
       # Need to refresh to get line numbers to display properly (and put cursor position to 0)
       @xml_editor.setCursor(0)
       @xml_editor.refresh()

common/lib/xmodule/xmodule/js/src/problem/edit.coffee

@@ -25,7 +25,6 @@ class @MarkdownEditingDescriptor extends XModule.Descriptor
       $(@element.find('.xml-box')).hide()
     else
       @createXMLEditor()
-      @xml_editor.display.wrapper.className += " CodeMirror-advanced";
 
   ###
   Creates the XML Editor and sets it as the current editor. If text is passed in,
@@ -54,7 +53,6 @@ class @MarkdownEditingDescriptor extends XModule.Descriptor
       @toggleCheatsheetVisibility()
     if @confirmConversionToXml()
       @createXMLEditor(MarkdownEditingDescriptor.markdownToXml(@markdown_editor.getValue()))
-      @xml_editor.display.wrapper.className += " CodeMirror-advanced";
       # Need to refresh to get line numbers to display properly (and put cursor position to 0)
       @xml_editor.setCursor(0)
       @xml_editor.refresh()