Prevent char[] leaks from gobbling heap

We've had some Jenkins crashes lately caused by OOME. After enabling heap dumps, I saw that a large proportion of the retained heap was large HTML strings attached to org.htmlparser.* classes. I spent quite some time today trying to track down where the references were coming from without success, so this is a blind fix that ensures that all Strings copied into the Rcov*Result objects have properly sized backing arrays.

If you aren't comfortable applying this patch, I can try to spend some more time understanding exactly how these strings are being retained.