After upgrading from 10.1-1.7, I have problems using the arrow keys to
navigate history when using the tui (readline is using vi editing).

To reproduce:

1. Edit your ~/.inputrc file, inserting
"set editing-mode vi"

2. Start gdb.

3. Type "tui enable".

4. Type "focus next" to switch focus back to the command line.

5. Try to use the up arrow key to go backwards in history (this was working
fine in 10.x). No reaction to the keystrokes at first, after a dozen of presses it
starts to show the previous entries, but it has switched to vi command mode.

It also seems to eat up other keystrokes, but I couldn't reproduce it
consistently.