Before this change UrlTag expanded URI vars and encoded them using
UriUtils.encodePath.
This change makes it possible to expand using
UriUtils.encodePathSegment, which means a "/" is encoded as "%2F".
To expand with path segment semantics, prefix the URI var name "/":
<spring:url value="/url/path/{/var}">
<spring:param name="var" value="my/Id" />
</spring:url>
Issue: SPR-11401