Remove struct tui_source_info

Remove struct tui_source_info

The tui_source_info struct is used as a member of the "detail" union
in tui_win_info, and this member of the union is only used by source
and disassembly windows.  This patch removes tui_source_info and moves
its members directly to tui_source_window_base.  This simplifies the
code by removing a layer of references from many places.  In a few
spots, a new cast was needed, but most of these will be removed by the
end of the series.

gdb/ChangeLog
2019-06-25  Tom Tromey  <tom@tromey.com>

	* tui/tui-winsource.c (tui_update_source_window)
	(tui_refill_source_window)
	(tui_source_window_base::do_scroll_horizontal)
	(tui_update_breakpoint_info, tui_set_exec_info_content)
	(tui_show_exec_info_content, tui_erase_exec_info_content)
	(tui_clear_exec_info_content): Update.
	* tui/tui-wingeneral.c (make_all_visible, tui_refresh_all):
	Update.
	* tui/tui-win.c (make_invisible_and_set_new_height)
	(make_visible_with_new_height): Update.
	* tui/tui-source.c (tui_set_source_content)
	(tui_show_symtab_source): Update.
	* tui/tui-layout.c (extract_display_start_addr)
	(show_source_disasm_command, show_data)
	(make_source_or_disasm_window)
	(show_source_or_disasm_and_command): Update.
	* tui/tui-disasm.c (tui_set_disassem_content): Simplify.
	(tui_disasm_window::do_scroll_vertical): Remove shadowing
	"gdbarch".
	* tui/tui-data.h (struct tui_source_info): Remove.  Move contents
	to tui_source_window_base.
	(struct tui_win_info) <detail>: Remove source_info member.
	(struct tui_source_window_base) <has_locator>: Inline.
	Move contents from tui_source_info; rename has_locator member to
	m_has_locator.
	(TUI_SRC_WIN, TUI_DISASM_WIN): Add casts.
	* tui/tui-data.c (tui_source_window_base::has_locator): Move to
	header file.
	(tui_source_window_base::clear_detail, ~tui_source_window_base):
	Simplify.
	(tui_free_all_source_wins_content): Cast to
	tui_source_window_base.