bug#3188: up-down arrows not functioning properly

[Chong Yidong]

> Open Emacs, display the scratch buffer, and place the cursor in the
> middle of the second line, then hit the up arrow: the cursor is moved
> at the beginning of the first line. Likewise, the down arrow moves the
> cursor at the beginning of the third line, instead of moving it one
> line up or down, but at the same column.

I can't reproduce this.  Please provide the exact sequence of keystrokes
you used, starting from `emacs -Q'.