tests/test-check-jshint.t

run-tests: don't append rtendtracing logs if pipe is /dev/null

If HGCATAPULTSERVERPIPE is not set, we set it to /dev/null, so we need to make
sure the value is not /dev/null before appending logs.

This fixes some of test-run-tests.t failures.

Differential Revision: https://phab.mercurial-scm.org/D4401

#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