Rename the "reset" method to "resize"

Rename the "reset" method to "resize"

tui_gen_win_info::reset really just resizes the window.  This patch
renames it to reflect this.

gdb/ChangeLog
2019-08-15  Tom Tromey  <tom@tromey.com>

	* tui/tui-winsource.h (struct tui_source_window_base) <resize>:
	Rename from reset.
	* tui/tui-winsource.c (tui_source_window_base::resize): Rename.
	* tui/tui-layout.c (show_source_disasm_command, show_data):
	Update.
	(tui_gen_win_info::resize): Rename.
	(show_source_or_disasm_and_command): Update.
	* tui/tui-data.h (struct tui_gen_win_info) <resize>: Rename from
	reset.