[Dsymutil][Debuginfo][NFC] #4 Refactor dsymutil to separate DWARF optimizing part.

Summary:
The primary goal of this refactoring is to separate DWARF optimizing part.
So that it could be reused by linker or by any other client.
There was a thread on llvm-dev discussing the necessity of such a refactoring:

http://lists.llvm.org/pipermail/llvm-dev/2019-September/135068.html.

This is a final part from series of patches for dsymutil.
Previous patches : D71068, D71839, D72476. This patch:

1. Creates lib/DWARFLinker interface :

   void addObjectFile(DwarfLinkerObjFile &ObjFile);
   bool link();
   void setOptions;

1. Moves all linking logic from tools/dsymutil/DwarfLinkerForBinary
   into lib/DWARFLinker.
2. Renames RelocationManager into AddressesManager.
3. Remarks creation logic moved from separate parallel execution
   into object file loading routine.

Testing: it passes "check-all" lit testing. MD5 checksum for clang .dSYM bundle
matches for the dsymutil with/without that patch.

Reviewers: JDevlieghere, friss, dblaikie, aprantl, jdoerfert

Reviewed By: JDevlieghere

Subscribers: merge_guards_bot, hiraditya, jfb, llvm-commits, probinson, thegameg

Tags: #llvm, #debug-info

Differential Revision: https://reviews.llvm.org/D72915

Author: avl-llvm

llvm/include/llvm/CodeGen/DIE.h

@@ -910,6 +910,9 @@ class DIELoc : public DIEValueList {
   ///
   unsigned ComputeSize(const AsmPrinter *AP) const;
 
+  // TODO: move setSize() and Size to DIEValueList.
+  void setSize(unsigned size) { Size = size; }
+
   /// BestForm - Choose the best form for data.
   ///
   dwarf::Form BestForm(unsigned DwarfVersion) const {
@@ -944,6 +947,9 @@ class DIEBlock : public DIEValueList {
   ///
   unsigned ComputeSize(const AsmPrinter *AP) const;
 
+  // TODO: move setSize() and Size to DIEValueList.
+  void setSize(unsigned size) { Size = size; }
+
   /// BestForm - Choose the best form for data.
   ///
   dwarf::Form BestForm() const {