tests/test-bad-extension.t

bookmarks: avoid redundant creation/assignment of "validdests" in "validdest()"

  $ echo 'raise Exception("bit bucket overflow")' > badext.py
  $ abspath=`pwd`/badext.py

  $ echo '[extensions]' >> $HGRCPATH
  $ echo "gpg =" >> $HGRCPATH
  $ echo "hgext.gpg =" >> $HGRCPATH
  $ echo "badext = $abspath" >> $HGRCPATH
  $ echo "badext2 =" >> $HGRCPATH

  $ hg -q help help
  *** failed to import extension badext from $TESTTMP/badext.py: bit bucket overflow
  *** failed to import extension badext2: No module named badext2
  hg help [-ec] [TOPIC]
  
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