Introduce and use ui_out_emit_table

Introduce and use ui_out_emit_table

This introduces ui_out_emit_table, similar to the other existing
ui_out RAII classes, and then uses it in a number of places.  This
replaces some cleanups.

ChangeLog
2017-08-03  Tom Tromey  <tom@tromey.com>

	* tracepoint.c (tvariables_info_1): Use ui_out_emit_table.
	(info_static_tracepoint_markers_command): Likewise.
	* solib.c (info_sharedlibrary_command): Use ui_out_emit_table.
	* skip.c (skip_info): Use ui_out_emit_table.
	* progspace.c (print_program_space): Use ui_out_emit_table.
	* osdata.c (info_osdata): Use ui_out_emit_table.
	* mi/mi-cmd-info.c (mi_cmd_info_ada_exceptions): Use
	ui_out_emit_table.
	* linux-thread-db.c (info_auto_load_libthread_db): Use
	ui_out_emit_table.
	* inferior.c (print_inferior): Use ui_out_emit_table.
	* gdb_bfd.c (maintenance_info_bfds): Use ui_out_emit_table.
	* breakpoint.c (breakpoint_1): Use ui_out_emit_table.
	* auto-load.c (auto_load_info_scripts): Use ui_out_emit_table.
	* ada-tasks.c (print_ada_task_info): Use ui_out_emit_table.
	* ui-out.h (class ui_out_emit_table): New.