tests/test-ssh-batch.t

pycompat: explicitly prefix builtin attr usage with `builtins.`

It doesn't seem like this would fix any bug, because the wrapped functions that
take bytes instead of str are defined after these calls.  But PyCharm was
flagging the second and third uses, saying "Type 'str' doesn't have expected
attribute 'decode'".  It wasn't flagging the first, but I changed it for
consistency.

  $ hg init a
  $ cd a
  $ touch a; hg commit -qAm_
  $ hg bookmark $(for i in $($TESTDIR/seq.py 0 20); do echo b$i; done)
  $ hg clone . ../b -q
  $ cd ../b

Checking that when lookup multiple bookmarks in one go, if one of them
fails (thus causing the sshpeer to be stopped), the errors from the
further lookups don't result in tracebacks.

  $ hg pull -r b0 -r nosuchbookmark $(for i in $($TESTDIR/seq.py 1 20); do echo -r b$i; done) ssh://user@dummy/$(pwd)/../a
  pulling from ssh://user@dummy/$TESTTMP/b/../a
  abort: unknown revision 'nosuchbookmark'
  [255]