tests: update test-bookmarks to pass the import checker

tests/test-bookmarks.t

@@ -948,8 +948,10 b' ensure changelog is written before bookm'
   $ echo a > a
 
   $ cat > $TESTTMP/pausefinalize.py <<EOF
+  > from __future__ import absolute_import
+  > import os
+  > import time
   > from mercurial import extensions, localrepo
-  > import os, time
   > def transaction(orig, self, desc, report=None):
   >    tr = orig(self, desc, report)
   >    def sleep(*args, **kwargs):