Don't call touchwin in tui_gen_win_info::refresh_window

Don't call touchwin in tui_gen_win_info::refresh_window

The call to touchwin in tui_gen_win_info::refresh_window was an
artifact of some earlier refactorings.  Testing shows it isn't needed
any more -- I believe it was only ever needed for the data item window
display problem; but that's been solved more locally.

gdb/ChangeLog
2019-08-30  Tom Tromey  <tom@tromey.com>

	* tui/tui-wingeneral.c (tui_gen_win_info::refresh_window): Don't
	call touchwin.