[lldb] Move clang-based files out of Symbol

Summary:
This change represents the move of ClangASTImporter, ClangASTMetadata,
ClangExternalASTSourceCallbacks, ClangUtil, CxxModuleHandler, and
TypeSystemClang from lldbSource to lldbPluginExpressionParserClang.h

This explicitly removes knowledge of clang internals from lldbSymbol,
moving towards a more generic core implementation of lldb.

Reviewers: JDevlieghere, davide, aprantl, teemperor, clayborg, labath, jingham, shafik

Subscribers: emaste, mgorny, arphaman, jfb, usaxena95, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D73661
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.cpp b/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.cpp
index bcf13e5..e70ab1c 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.cpp
@@ -9,7 +9,9 @@
 #include "IRForTarget.h"
 
 #include "ClangExpressionDeclMap.h"
+#include "ClangUtil.h"
 
+#include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/InstrTypes.h"
@@ -27,8 +29,6 @@
 #include "lldb/Core/dwarf.h"
 #include "lldb/Expression/IRExecutionUnit.h"
 #include "lldb/Expression/IRInterpreter.h"
-#include "lldb/Symbol/TypeSystemClang.h"
-#include "lldb/Symbol/ClangUtil.h"
 #include "lldb/Symbol/CompilerType.h"
 #include "lldb/Utility/ConstString.h"
 #include "lldb/Utility/DataBufferHeap.h"