Merge branch 'js/test-lint-pathname'

Merge branch 'js/test-lint-pathname'

The "t/" hierarchy is prone to get an unusual pathname; "make test"
has been taught to make sure they do not contain paths that cannot
be checked out on Windows (and the mechanism can be reusable to
catch pathnames that are not portable to other platforms as need
arises).

* js/test-lint-pathname:
  t/Makefile: ensure that paths are valid on platforms we care