Test for different methods in `ProjectDefinition >> #postLoadJavaHook` This commit just changes the clumsy test for compiled class libraries to use multiple different methods. `#classNamesAndAttributes` may be missing in (pure) Pharo `PackageManifests`. `#mandatoryPreRequisites` may be missing in some old project definitions created before (single) `#preRequisites` have been split to `#mandatoryPreRequisites` and `#requiredPreRequisites`. Sigh.

# automagically generated by the project definition
# this file is needed for stc to be able to compile modules independently.
# it provides information about a classes filename, category and especially namespace.
stx_libjava_tests stx_libjava_tests stx:libjava/tests '* Projects & Packages *' 3