Attempt at fixing assertion from reverse search

Trying to fix gh-10014, though I can't reproduce the problem to test it.

PR against 5.x because I think this is only needed for Python 2.

IPython/terminal/interactiveshell.py

@@ -239,7 +239,7 b' class TerminalInteractiveShell(InteractiveShell):'
             # Ignore blank lines and consecutive duplicates
             cell = cell.rstrip()
             if cell and (cell != last_cell):
-                history.append(cell)
+                history.append(cast_unicode_py2(cell))
                 last_cell = cell
 
         self._style = self._make_style_from_name_or_cls(self.highlighting_style)