Move StructuredData from Core to Utility

Summary:
It had a dependency on StringConvert and file reading code, which is not
in Utility. I've replaced that code by equivalent llvm operations.

I've added a unit test to demonstrate that parsing a file still works.

Reviewers: zturner, jingham

Subscribers: kubamracek, mgorny, lldb-commits

Differential Revision: https://reviews.llvm.org/D34625

llvm-svn: 306394

lldb/source/Target/ThreadSpec.cpp

@@ -11,9 +11,9 @@
 // C++ Includes
 // Other libraries and framework includes
 // Project includes
-#include "lldb/Target/Thread.h"
-#include "lldb/Core/StructuredData.h"
 #include "lldb/Target/ThreadSpec.h"
+#include "lldb/Target/Thread.h"
+#include "lldb/Utility/StructuredData.h"
 
 using namespace lldb;
 using namespace lldb_private;