Merge branch 'js/test-lint-pathname' into maint

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