Split elf_writer_debug.cc to several files.

Refactoring only. The file has grown significantly over time,
and it is time to split it so it can be better managed.

Change-Id: Idce0231718add722292f4701df353d5baf31de5f
diff --git a/compiler/oat_writer.cc b/compiler/oat_writer.cc
index 590c0f8..47dcfd5 100644
--- a/compiler/oat_writer.cc
+++ b/compiler/oat_writer.cc
@@ -811,7 +811,7 @@
         // Record debug information for this function if we are doing that.
         const uint32_t quick_code_start = quick_code_offset -
             writer_->oat_header_->GetExecutableOffset() - thumb_offset;
-        writer_->method_info_.push_back(dwarf::MethodDebugInfo {
+        writer_->method_info_.push_back(debug::MethodDebugInfo {
             dex_file_,
             class_def_index_,
             it.GetMemberIndex(),