Move code related to debug info generation to its own directory.

debug/dwarf/ contains helper classes which hide the details
of the DWARF file format. It acts as independent DWARF library.

debug/ contains ART-specific code which generates ELF debug
sections (which includes non-DWARF sections like .symtab).

Change-Id: Id351f604e4e64be2ca395a78324ea02e30481497
diff --git a/compiler/oat_writer.cc b/compiler/oat_writer.cc
index 90ac499..590c0f8 100644
--- a/compiler/oat_writer.cc
+++ b/compiler/oat_writer.cc
@@ -29,11 +29,11 @@
 #include "class_linker.h"
 #include "compiled_class.h"
 #include "compiled_method.h"
-#include "dex_file-inl.h"
+#include "debug/method_debug_info.h"
 #include "dex/verification_results.h"
+#include "dex_file-inl.h"
 #include "driver/compiler_driver.h"
 #include "driver/compiler_options.h"
-#include "dwarf/method_debug_info.h"
 #include "gc/space/image_space.h"
 #include "gc/space/space.h"
 #include "handle_scope-inl.h"