Problem:
When not inside an Ex command, screen_resize() calls update_screen(),
which calls screenclear() and set the screen as valid. However, when
inside an Ex command, redrawing is postponed so update_screen() screen
doesn't do anything, and the screen is still invalid after the resize,
causing ui_comp_raw_line() to be no-op until update_screen() is called
on the main loop.
Solution:
Restore the call to screenclear() inside screen_resize() so that the
screen is invalid after screen_resize(). Since screenclear() changes
redraw type from UPD_CLEAR to UPD_NOT_VALID, it is called at most once
for each resize, so this shouldn't change how much code is run in the
common (not inside an Ex command) case.
c2375efe56