Only send sync execution command output to the UI that ran the command

Only send sync execution command output to the UI that ran the command

Currently when a "step", "next", etc. finishes, the current source
line is printed on all console UIs.

This patch makes the CLI and TUI interpreters reuse MI's logic to only
emit console output related to a synchronous command on the
console-like interpreter that started the command in the first place.

gdb/ChangeLog:
2016-06-21  Pedro Alves  <palves@redhat.com>

	* cli/cli-interp.c (cli_on_normal_stop): Bail out early if there's
	nothing to print.  Use should_print_stop_to_console.
	* tui/tui-interp.c (tui_on_normal_stop): Likewise.