[LLI] Replace the LLI remote-JIT support with the new ORC remote-JIT components.

[LLI] Replace the LLI remote-JIT support with the new ORC remote-JIT components.

The new ORC remote-JITing support provides a superset of the old code's
functionality, so we can replace the old stuff. As a bonus, a couple of
previously XFAILed tests have started passing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257343 91177308-0d34-0410-b5e6-96231b3b80d8