[Z] Fix incomplete_type on ZLinux when compiling RemoteJITUtils

[tungld]

Summary

When compiling on ZLinux, we got this error:

/llvm-project/llvm/examples/OrcV2Examples/LLJITWithRemoteDebugging/RemoteJITUtils.h:80:65:   required from here...
/usr/include/c++/7/bits/unique_ptr.h:76:22: error: invalid application of 'sizeof' to incomplete type 'llvm::orc::RemoteExecutorProcessControl'
  static_assert(sizeof(_Tp)>0,

This patch just removes nullptr from the initialization of std::unique_ptr<RemoteExecutorProcessControl> to avoid the issue.

[lhames]

LGTM. Do you have commit access? If not I'll be happy to commit on your behalf.

[tungld]

I don't have. This is my information: "name (email)" : "Tung D. Le ([e-mail])". Thank you!

llvm/examples/OrcV2Examples/LLJITWithRemoteDebugging/RemoteJITUtils.h

public:
   loadDylib(StringRef RemotePath);
 
   Expected<int> runAsMain(JITEvaluatedSymbol MainSym,
                           ArrayRef<std::string> Args);
 
   virtual ~JITLinkExecutor();
 
 protected:
-  std::unique_ptr<RemoteExecutorProcessControl> OwnedEPC{nullptr};
+  std::unique_ptr<RemoteExecutorProcessControl> OwnedEPC;
   RemoteExecutorProcessControl *EPC{nullptr};
 
   JITLinkExecutor();
 };
 
 /// JITLinkExecutor that runs in a child process on the local machine.
 class ChildProcessJITLinkExecutor : public JITLinkExecutor {
 public: