We need to provide tools support for MVM. These tools include jstack, jmap etc. Essentially, we need to pass such requests such as stack dump or heap dump to the MServer process and let it choose what to do. For stack dump, the MServer should just dump the stack associated with the requesting mtask. For heap dump, until the time the MServer implements per-task heap, the possible implementation for now is to dump the whole heap.
Due to the complexity of implementing jstack, I will file another bug to address that. For this CR, we want to only address jmap support.