Use __name__ instead of "test_regex" as the module name in the

warnings.filterwarnings() call.  This suppresses the warning when the
module is imported with its full name (test.test_regex) too.

Lib/test/test_regex.py

 from test_support import verbose
 import warnings
 warnings.filterwarnings("ignore", "the regex module is deprecated",
-                        DeprecationWarning, "test_regex")
+                        DeprecationWarning, __name__)
 import regex
 from regex_syntax import *