fix enum and backslash warnings (GH-25861) (GH-25871)

- Enum warning in test_faulthandler
- backslash warning in test_ipaddress
(cherry picked from commit 652bcd9f9cd2ed89b5fa958f8456556aa43b48cc)

Co-authored-by: Ethan Furman <ethan@stoneleaf.us>

Co-authored-by: Ethan Furman <ethan@stoneleaf.us>
diff --git a/Lib/test/test_ipaddress.py b/Lib/test/test_ipaddress.py
index cdd9880..90559ce 100644
--- a/Lib/test/test_ipaddress.py
+++ b/Lib/test/test_ipaddress.py
@@ -97,7 +97,7 @@ class CommonTestMixin_v4(CommonTestMixin):
 
     def test_leading_zeros(self):
         # bpo-36384: no leading zeros to avoid ambiguity with octal notation
-        msg = "Leading zeros are not permitted in '\d+'"
+        msg = "Leading zeros are not permitted in '\\d+'"
         addresses = [
             "000.000.000.000",
             "192.168.000.001",