tests/test-check-jshint.t

windows: gracefully handle when the username cannot be determined

This assumes implementation details, but I don't see any other way than to check
the environment variables ourselves (which would miss out on any future
enhancements that Python may make).  This was originally reported as
https://foss.heptapod.net/mercurial/tortoisehg/thg/-/issues/5835.

#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