Squish: Some smaller refactorings

Change-Id: I5f8b5ec982e8a38d32ba15d81317c2308dc00106
Reviewed-on: http://codereview.qt-project.org/5544
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Bill King <bill.king@nokia.com>
Reviewed-by: Robert Löhning <robert.loehning@nokia.com>

tests/system/shared/editor_utils.py

@@ -56,3 +56,8 @@ def markText(editor, startPosition, endPosition):
     cursor.setPosition(endPosition, QTextCursor.KeepAnchor)
     editor.setTextCursor(cursor)
 
+# works for all standard editors
+def replaceEditorContent(editor, newcontent):
+    type(editor, "<Ctrl+A>")
+    type(editor, "<Delete>")
+    type(editor, newcontent)