Remove tui_win_info::refresh_all

Remove tui_win_info::refresh_all

The TUI has two duplicate "re-render this window" methods, "rerender"
and "refresh_all".  They differ only slightly in semantics, so I
wanted to see if they could be unified.

After looking into this, I decided that refresh_all was not needed.
There are 4 calls to tui_refresh_all_win (the only caller of this
method):

1. tui_enable.  This sets the layout, which renders the windows.

2. tui_cont_sig.  Here, I think it's sufficient to simply redraw the
   current window contents from the curses backing store, because gdb
   state didn't change while it was suspended

3. tui_dispatch_ctrl_char.  This is the C-l handler, and here it's
   explicitly enough to just refresh the screen (as above).

4. tui_refresh_all_command.  This is the command equivalent of C-l.

So, this patch removes this method entirely and simplifies
tui_refresh_all_win.

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

	* tui/tui-winsource.h (struct tui_source_window_base)
	<refresh_all>: Don't declare.
	* tui/tui-winsource.c (tui_source_window_base::refresh_all):
	Remove.
	* tui/tui-win.c (tui_refresh_all_win): Don't call refresh_all or
	tui_show_locator_content.
	* tui/tui-regs.h (struct tui_data_window) <refresh_all>: Don't
	declare.
	* tui/tui-regs.c (tui_data_window::refresh_all): Remove.
	* tui/tui-data.h (struct tui_win_info) <refresh_all>: Don't
	declare.