Fix the cppunit tests to use setUp() rather than an static constructor to

Fix the cppunit tests to use setUp() rather than an static constructor to
initialize memory pools etc.

Static constructors is dangerous in that you don't know for sure
in which order they will be called. The recent String pool change
where the object size is dynamically calculated on startup is and
example, where the requested pool size had not yet been calculated
before the pools was created.