HelpLinksChecker.class does not work properly when run in Windows

HelpLinksChecker.class with -nointernet does not work properly when run in Windows because the correct file separator used in the links in the help/html pages is '/' which does not work in local filesystem check when run as a gradle task in Windows.
Because this fails, the task in build.gradle fails and blocks the compilation of the jalview.jar and everything else beyond.