[ORC] Add SimpleRemoteMemoryMapper (new MemoryMapper implementation). (#163707)
SimpleRemoteMemoryMapper is a MemoryMapper implementation that manages
remote memory via EPC-calls to reserve, initialize, deinitialize, and
release operations. It is compatible with the
SimpleExecutorMemoryManager backend, and its introduction allows
MapperJITLinkMemoryManager to use this backend.
It is also intended to be compatible with the
orc_rt::SimpleNativeMemoryMap backend.