This reintroduces "[ORC] Introduce EPCGenericRTDyldMemoryManager." (bef55a2b47) and "[lli] Add ChildTarget dependence on OrcTargetProcess library." (7a219d801b) which were reverted in99951a5684due to bot failures. The root cause of the bot failures should be fixed by "[ORC] Fix uninitialized variable." (0371049277) and "[ORC] Wait for handleDisconnect to complete in SimpleRemoteEPC::disconnect." (320832cc9b).