Fix Debug Console when attaching to IPython process (PY-20531)

python/helpers/pydev/_pydev_bundle/pydev_ipython_console_011.py

@@ -313,16 +313,17 @@ class _PyDevFrontEnd:
     version = release.__version__
 
     def __init__(self, show_banner=True):
-
         # Create and initialize our IPython instance.
-        self.ipython = PyDevTerminalInteractiveShell.instance()
+        if hasattr(PyDevTerminalInteractiveShell, '_instance') and PyDevTerminalInteractiveShell._instance is not None:
+            self.ipython = PyDevTerminalInteractiveShell._instance
+        else:
+            self.ipython = PyDevTerminalInteractiveShell.instance()
 
         if show_banner:
             # Display the IPython banner, this has version info and
             # help info
             self.ipython.show_banner()
 
-
         self._curr_exec_line = 0
         self._curr_exec_lines = []