GenShen sets up separate memory managers for old and young generations, but the updates do not update these managers as intended, lumping all updates into the legacy Shenandoah manager/bean/pool. The existing tests TestMemoryMXBeans and TestMemoryPools don't catch the issue since the mangers are set up, but the old manager isn't updated. Since GenShen has 3 types of collections: young, old, and global, there may also be a need for distinguishing global from young and old.

This ticket is to make sure legacy Shenandoah beans are correctly updated for each type of collection and memory pools in the generational case.