gh-71339: Fix an order-dependent failure in test_unittest (GH-129133)

It failed if it was preceded by test_builtin.

Author: serhiy-storchaka

Lib/test/test_builtin.py

@@ -1833,7 +1833,10 @@ def test_bug_27936(self):
 
     def test_setattr(self):
         setattr(sys, 'spam', 1)
-        self.assertEqual(sys.spam, 1)
+        try:
+            self.assertEqual(sys.spam, 1)
+        finally:
+            del sys.spam
         self.assertRaises(TypeError, setattr)
         self.assertRaises(TypeError, setattr, sys)
         self.assertRaises(TypeError, setattr, sys, 'spam')

Lib/test/test_unittest/test_case.py

@@ -801,9 +801,9 @@ def testAssertHasAttr(self):
         self.assertEqual(str(cm.exception),
                 "type object 'List' has no attribute 'spam'")
         with self.assertRaises(self.failureException) as cm:
-            self.assertHasAttr(sys, 'spam')
+            self.assertHasAttr(sys, 'nonexistent')
         self.assertEqual(str(cm.exception),
-                "module 'sys' has no attribute 'spam'")
+                "module 'sys' has no attribute 'nonexistent'")
 
         with self.assertRaises(self.failureException) as cm:
             self.assertHasAttr(a, 'y', 'ababahalamaha')