Merge branch 'tr/perl-keep-stderr-open'

Merge branch 'tr/perl-keep-stderr-open'

Closing (not redirecting to /dev/null) the standard error stream is
not a very smart thing to do.  Later open may return file
descriptor #2 for unrelated purpose, and error reporting code may
write into them.

* tr/perl-keep-stderr-open:
  t9700: do not close STDERR
  perl: redirect stderr to /dev/null instead of closing