UnixConsole: raise EOFError in case input_fd is not a TTY

This is required for when the UnixConsole instance was created with
stdin being a terminal, but then later not so anymore.

E.g. having used pdbpp before pytest captures output
(`pdb.set_trace()`), and then continuing (`c`).
pytest is capturing output by now then, but the debugging plugin (which
suspends capturing) might not be active yet (pytest_load_initial_conftests).

This patch makes it raise `BdbQuit` then "correctly".

pyrepl/reader.py

@@ -478,8 +478,8 @@ def prepare(self):
         """Get ready to run.  Call restore when finished.  You must not
         write to the console in between the calls to prepare and
         restore."""
+        self.console.prepare()
         try:
-            self.console.prepare()
             self.arg = None
             self.screeninfo = []
             self.finished = 0

pyrepl/unix_console.py

@@ -354,7 +354,11 @@ def move_cursor(self, x, y):
 
     def prepare(self):
         # per-readline preparations:
-        self.__svtermstate = tcgetattr(self.input_fd)
+        try:
+            self.__svtermstate = tcgetattr(self.input_fd)
+        except termios.error:  # (25, 'Inappropriate ioctl for device')
+            # assert not os.fdopen(self.input_fd).isatty()
+            raise EOFError
         raw = self.__svtermstate.copy()
         raw.iflag |= termios.ICRNL
         raw.iflag &= ~(termios.BRKINT | termios.INPCK |