gh-108416: Mark slow test methods with @requires_resource('cpu') (GH-108421)

Only mark tests which spend significant system or user time,
by itself or in subprocesses.

Lib/test/test_multibytecodec.py

@@ -363,6 +363,7 @@ class Test_ISO2022(unittest.TestCase):
             e = '\u3406'.encode(encoding)
             self.assertFalse(any(x > 0x80 for x in e))
 
+    @support.requires_resource('cpu')
     def test_bug1572832(self):
         for x in range(0x10000, 0x110000):
             # Any ISO 2022 codec will cause the segfault