Reinstate "Nuke the old JIT."

Approved by Jim Grosbach, Lang Hames, Rafael Espindola.

This reinstates commits r215111, 215115, 215116, 215117, 215136.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216982 91177308-0d34-0410-b5e6-96231b3b80d8

tools/llvm-jitlistener/llvm-jitlistener.cpp

@@ -149,7 +149,6 @@ protected:
       .setEngineKind(EngineKind::JIT)
       .setErrorStr(&Error)
       .setJITMemoryManager(MemMgr)
-      .setUseMCJIT(true)
       .create());
     if (Error.empty() == false)
       errs() << Error;