resourceloader: Improve code coverage

resourceloader: Improve code coverage

* Missing cases for StartupModule::getModuleRegistrations
  (now 100% covered)
  - Raw modules are omitted from the manifest.
    E.g. The base modules ('jquery', 'mediawiki') are raw modules
    that we don't register client side (they can't load themselves).
  - Exceptions from getVersionHash() are caught.
  - Oversized versions are re-hashed.

* Missing cases for ResourceLoader::makeLoaderRegisterScript.
  (now 100% covered)

* Missing cases for ResourceLoader::getModule.
  (now 100% covered)

Change-Id: If9717a48195fc6ae776da5d0e86f323d7f60426d