Modtest/Sigtest should be able to return ModuleDescription instance from parsing module-info.class and ClassDescription instance from parsing class files from corresponding module.

This requirements stems from tests on JSR269 which currently verify model produced by JSR269 implementation under test against golden XML files. These golden XML files are created during JCK build by JSR269 RI run on corresponding sources or class files. These scheme assumes that JSR269 RI works correctly and produces correct model to be stored in XML file. But this actually should be checked. While we have technical difficulties in checking RI annotation processing on sources, RI annotation processing on class files can be verified against structures created by Sitest/Modtest from parsing class-files. This is how JSR269 tests worked before, now we need them to work this way with modules.