perf tools: Add the bash completion for listing subsubcommands of perf test

The bash completion does not support listing subsubcommands for 'perf
test <TAB>', so fix it.

Example:

Before this patch:

$ perf test <TAB>
$

As shown above, the subsubcommands of perf test does not come out.

After this patch:

$ perf test <TAB>
list

As shown above, the subsubcommands of perf test can come out now.

Signed-off-by: Yunlong Song <[e-mail]>
Tested-by: Arnaldo Carvalho de Melo <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Wang Nan <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/perf-completion.sh

···
 		__perfcomp_colon "$evts" "$cur"
 	else
 		# List subcommands for perf commands
-		if [[ $prev_skip_opts == @(kvm|kmem|mem|lock|sched|data|help|script) ]]; then
+		if [[ $prev_skip_opts == @(kvm|kmem|mem|lock|sched|data|help|script|test) ]]; then
 			subcmds=$($cmd $prev_skip_opts --list-cmds)
 			__perfcomp_colon "$subcmds" "$cur"
 		fi

tools/perf/tests/builtin-test.c

···
 
 int cmd_test(int argc, const char **argv, const char *prefix __maybe_unused)
 {
-	const char * const test_usage[] = {
+	const char *test_usage[] = {
 	"perf test [<options>] [{list <test-name-fragment>|[<test-name-fragments>|<test-numbers>]}]",
 	NULL,
 	};
···
 		    "be more verbose (show symbol address, etc)"),
 	OPT_END()
 	};
+	const char * const test_subcommands[] = { "list", NULL };
 	struct intlist *skiplist = NULL;
         int ret = hists__init();
 
         if (ret < 0)
                 return ret;
 
-	argc = parse_options(argc, argv, test_options, test_usage, 0);
+	argc = parse_options_subcommand(argc, argv, test_options, test_subcommands, test_usage, 0);
 	if (argc >= 1 && !strcmp(argv[0], "list"))
 		return perf_test__list(argc, argv);