Issue #25487: Fix tests not updated when the imp module moved to a
DeprecationWarning.

Thanks to Martin Panter for finding the tests.
diff --git a/Lib/modulefinder.py b/Lib/modulefinder.py
index 50f2462..4a2f1b5 100644
--- a/Lib/modulefinder.py
+++ b/Lib/modulefinder.py
@@ -10,7 +10,7 @@
 import struct
 import warnings
 with warnings.catch_warnings():
-    warnings.simplefilter('ignore', PendingDeprecationWarning)
+    warnings.simplefilter('ignore', DeprecationWarning)
     import imp
 
 # XXX Clean up once str8's cstor matches bytes.