perf trace: Free strings in trace__parse_events_option()

ASan reports several memory leaks running:

  # perf test "88: Check open filename arg using perf trace + vfs_getname"

The fourth of these leaks is related to some strings never being freed
in trace__parse_events_option.

This patch adds the missing frees.

Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/34d08535b11124106b859790549991abff5a7de8.1626343282.git.rickyman7@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-trace.c

@@ -4659,6 +4659,9 @@ do_concat:
 		err = parse_events_option(&o, lists[0], 0);
 	}
 out:
+	free(strace_groups_dir);
+	free(lists[0]);
+	free(lists[1]);
 	if (sep)
 		*sep = ',';