LoadCache fails to insert some classes to cache causing repeated, costly lookups

Byteman uses class LoadCache to cache classes by name. This is intended to avoid continual scanning of the loaded classes list when scanning the class hierarchy in the agent transformer. It also allows the type checker to find a least upper bound super without inadvertently loading classes. The current implementation successfully finds classes but fails to insert them into the class in specific circumstances. The failure case occurs when the referring class is loaded by the system loader or an application loader but the referenced class is loaded by the bootstrap loader.