perf sched: Implement the 'perf sched record' subcommand

Implement the 'perf sched record' subcommand that adds a
default list of events, turns on raw sampling and system-wide
tracing and passes off the rest of the command to perf record.

This is more convenient than having to specify the events all
the time.

Before:

 $ perf record -a -R -e sched:sched_switch:r -e sched:sched_stat_wait:r -e sched:sched_stat_sleep:r -e sched:sched_stat_iowait:r -e sched:sched_process_exit:r -e sched:sched_process_fork:r -e sched:sched_wakeup:r -e sched:sched_migrate_task:r -c 1 sleep 1

After:

 $ perf sched record -f sleep 1

Also fix an assumption in the event string parser that assumed
that strings passed in can be modified. (In this case they wont
be as they come from a readonly constant section.)

Signed-off-by: Ingo Molnar <mingo@elte.hu>

tools/perf/util/parse-events.c

@@ -525,7 +525,8 @@ static enum event_result parse_tracepoint_event(const char **strp,
 
 	flags = strchr(evt_name, ':');
 	if (flags) {
-		*flags = '\0';
+		/* split it out: */
+		evt_name = strndup(evt_name, flags - evt_name);
 		flags++;
 	}