[test/server] Only use configcls with statement timeout when needed Other tests in PostgresFTITC class apparently do not make use of this particular configuration.

[server/test] Add an assertion in test_statement_timeout

[datafeed] minor cleanups to cwxml parser

[datafeed] don't allow arbitrary kwargs on DatafeedParser initializer else they will be handled nicely by appobject base class, while we rather want an error in the case of a source parser (arguable).