Fix test skipping in multibyte codec tests

Lib/test/test_bytes.py

@@ -935,7 +935,7 @@ class AssortedBytesTest(unittest.TestCase):
             self.assertRaises(BytesWarning, operator.eq, bytearray(b''), '')
             self.assertRaises(BytesWarning, operator.ne, bytearray(b''), '')
         else:
-            # raise test.support.TestSkipped("BytesWarning is needed for this test: use -bb option")
+            # self.skipTest("BytesWarning is needed for this test: use -bb option")
             pass
 
     # Optimizations:

Lib/test/test_multibytecodec_support.py

@@ -279,7 +279,7 @@ class TestBase_Mapping(unittest.TestCase):
         try:
             self.open_mapping_file() # test it to report the error early
         except IOError:
-            raise support.TestSkipped("Could not retrieve "+self.mapfileurl)
+            self.skipTest("Could not retrieve "+self.mapfileurl)
 
     def open_mapping_file(self):
         return support.open_urlresource(self.mapfileurl)