Backport r60208, skip some tests for huge passwd/group files.
diff --git a/Lib/test/test_grp.py b/Lib/test/test_grp.py
index 08958ba..a8dcb63 100755
--- a/Lib/test/test_grp.py
+++ b/Lib/test/test_grp.py
@@ -25,6 +25,9 @@
         for e in entries:
             self.check_value(e)
 
+        if len(entries) > 1000:  # Huge group file (NIS?) -- skip the rest
+            return
+
         for e in entries:
             e2 = grp.getgrgid(e.gr_gid)
             self.check_value(e2)