Tighten up some warning filters, and break some dependencies on the

order in which the tests are normally run.

Lib/test/test_coercion.py

@@ -112,6 +112,7 @@ def do_prefix_binops():
 
 warnings.filterwarnings("ignore",
                         r'complex divmod\(\), // and % are deprecated',
-                        DeprecationWarning)
+                        DeprecationWarning,
+                        r'test_coercion$')
 do_infix_binops()
 do_prefix_binops()