bump sesame to 2.7.10 and fix tests relating to change in behaviour for null literal creation

should not be relying on a particular behaviour for null literal creation, in particularly not an NPE or assertion error
ANY23-181 Upgrade NekoHTML to 1.9.20
Merge branch 'master' of https://git-wip-us.apache.org/repos/asf/any23
Merge branch 'master' into ANY23-akn