MemoryLeak in JaasSecurityManager::DomainInfo

There is a memory leak caused by the JaasSecurityManager::DomainInfo
holding a reference to the LoginContext.

Internally, this holds a reference to the context classloader.

If this information is cached and then the classloader undeployed,
the classloader and all associated classes/proxies/static data
don't get garbage collected until this information is flushed.