tests/test-check-jshint.t

tests: allow optional output when `test-lfs-server` is sent SIGTERM

I guess this has only ever been tested on Windows, but on macOS, the test was
failing with changes like:

    +++ /private/tmp/mercurial-ci/tests/test-lfs-test-server.t#git-server.err
    @@ -858,6 +858,7 @@
     (Restart the server in a different location so it no longer has the content)

       $ "$PYTHON" $RUNTESTDIR/killdaemons.py $DAEMON_PIDS
    +  $TESTTMP.sh: line 153: 38639 Terminated: 15          lfs-test-server > lfs-server.log 2>&1

     #if hg-server
       $ cat $TESTTMP/access.log $TESTTMP/errors.log

#require test-repo jshint hg10

  $ . "$TESTDIR/helpers-testrepo.sh"

run jshint on all tracked files ending in .js except vendored dependencies

  $ cd "`dirname "$TESTDIR"`"

  $ testrepohg locate 'set:**.js' \
  > 2>/dev/null \
  > | xargs jshint