Upgrade HSQLDB to >= 2.3.3 to fix 2.3.2 regression

As discussed on http://tomee-openejb.979440.n4.nabble.com/Upgrade-HSQLDB-to-fix-regression-on-2-3-2-td4683088.html

TomEE 1.7, 7 or 8 bundles HSQLDB version 2.3.2, but this version has a major regression for our use case:

http://hsqldb.org/doc/2.0/changelist_2_0.txt

28 June 2015 - version 2.3.3
...
– fixed regression in 2.3.2, multiple rows with partial null values could
not be inserted in UNIQUE indexes
...

I will create a PR on GitHub asap