Adds a rough sketch of what will be a test harness, currently only supported
on OS X:
- Launch a child process: an executable written in Swift
- Receive the child process's Mach port
- Receive reflection section addresses and the address of a heap instance
of interest
- Perform field type lookup on the instance remotely (TODO)
- Don't depend on LLVM Support and swiftBasic as this will bring in
llvmSupport and other heavy dependencies, which we don't build for
non-host architectures right now anyway.
- Add a reader template that works with the same (albeit somewhat
clunky) interface in-process with the runtime and remotely, by having
the memory tool supply a function that will copy data from the remote
process.
- Add a Buffer type to abstract indirecting pointers in a remote address
space, which is handled by the memory reader.
- Start sketching out the C remote mirrors interface.
