Input prompt for the Python Interactive window doesn't support up arrow correctly for single item

[rchiodo]

In the normal command prompt if you type something like :

1

And then hit enter, on the next line, hitting 'up' will cause 1 to appear.

If you erase the line and hit up, 1 will continue to appear. For us, the 1 will appear once, but then the up position will go beyond the end and we'll never allow another up.