Fix Edit Field long lines changing text cursor behaviour

[wiktor-obrebski]

Fix EditField long lines cursor behaviour described in this issue:

The scenario requires a couple of commands in gui/launcher history: (e.g.)
:lua print'jh 0123456789 0123456789 0123456789 jl'(the "long" entry)
extend the string (or shrink the window) as necessary so that it is longer
than the gui/launcher command line is wide
gui/gm-unit (the "short" entry)
Then,
Alt-s to focus the search field,
type jj to find the long entry,
Ctrl-u to clear the search field,
type unit to find the short entry,
Esc to go back to the command line field.
The command line EditField looks like it is empty with just a cursor. The short entry is
there, but it is "scrolled" out of view to the left. Moving the cursor to the
left will start to reveal the short entry.