Remove the TUI execution info window

The TUI execution info window is unusual in that it is always linked
to a source or disassembly window.  Even updates of its content are
handled by the source window, so it really has no life of its own.

This patch removes this window entirely and puts its functionality
directly into the source window.  This simplifies the code somewhat.

This is a user-visible change, because now the box around the source
(or disassembly) window encloses the execution info as well.  I
consider this an improvement as well, though.

Note that this patch caused ncurses to start emitting the "CSI Z"
sequence, so I've added this to the test suite terminal
implementation.

gdb/ChangeLog
2019-08-16  Tom Tromey  <tom@tromey.com>

	* tui/tui.h (enum tui_win_type) <EXEC_INFO_WIN>: Remove.
	* tui/tui-winsource.h (struct tui_exec_info_window): Remove.
	(struct tui_source_window_base) <make_visible, refresh_window,
	resize>: Remove methods.
	<execution_info>: Remove field.
	* tui/tui-winsource.c (tui_source_window_base::do_erase_source_content)
	(tui_show_source_line, tui_source_window_base)
	(~tui_source_window_base): Update.
	(tui_source_window_base::resize)
	(tui_source_window_base::make_visible)
	(tui_source_window_base::refresh_window): Remove.
	(tui_source_window_base::update_exec_info): Update.
	* tui/tui-source.c (tui_source_window::set_contents): Update.
	* tui/tui-disasm.c (tui_disasm_window::set_contents): Update.

gdb/testsuite/ChangeLog
2019-08-16  Tom Tromey  <tom@tromey.com>

	* lib/tuiterm.exp (_csi_Z): New proc.
	* gdb.tui/basic.exp: Update window positions.
	* gdb.tui/empty.exp: Update window positions.