perf test: S390 does not support watchpoints in test 22

S390 does not support the perf_event_open system call for
attribute type PERF_TYPE_BREAKPOINT. This results in test
failure for test 22:

  [root@s8360046 perf]# ./perf test 22
  22: Watchpoint                                :
  22.1: Read Only Watchpoint                    : FAILED!
  22.2: Write Only Watchpoint                   : FAILED!
  22.3: Read / Write Watchpoint                 : FAILED!
  22.4: Modify Watchpoint                       : FAILED!
  [root@s8360046 perf]#

Add s390 support to avoid these tests being executed on
s390 platform:

  [root@s8360046 perf]# ./perf test 22
  [root@s8360046 perf]# ./perf test -v 22
  22: Watchpoint                                : Disabled
  [root@s8360046 perf]#
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Link: http://lkml.kernel.org/r/20180928105335.67179-1-tmricht@linux.ibm.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/builtin-test.c

@@ -123,6 +123,7 @@ static struct test generic_tests[] = {
 	{
 		.desc = "Watchpoint",
 		.func = test__wp,
+		.is_supported = test__wp_is_supported,
 		.subtest = {
 			.skip_if_fail	= false,
 			.get_nr		= test__wp_subtest_get_nr,

tools/perf/tests/tests.h

@@ -109,6 +109,7 @@ int test__unit_number__scnprint(struct test *test, int subtest);
 int test__mem2node(struct test *t, int subtest);
 
 bool test__bp_signal_is_supported(void);
+bool test__wp_is_supported(void);
 
 #if defined(__arm__) || defined(__aarch64__)
 #ifdef HAVE_DWARF_UNWIND_SUPPORT

tools/perf/tests/wp.c

@@ -227,3 +227,15 @@ int test__wp(struct test *test __maybe_unused, int i)
 
 	return !wp_testcase_table[i].target_func() ? TEST_OK : TEST_FAIL;
 }
+
+/* The s390 so far does not have support for
+ * instruction breakpoint using the perf_event_open() system call.
+ */
+bool test__wp_is_supported(void)
+{
+#if defined(__s390x__)
+	return false;
+#else
+	return true;
+#endif
+}