Directory restructuring of object.h

Break object.h into constituent files.
Reduce number of #includes in other GC header files.
Introduce -inl.h files to avoid mirror files #include-ing each other.
Check invariants of verifier RegTypes for all constructors.

Change-Id: Iecf1171c02910ac152d52947330ef456df4043bc
diff --git a/src/dex_instruction.cc b/src/dex_instruction.cc
index d3aa238..55f6eca 100644
--- a/src/dex_instruction.cc
+++ b/src/dex_instruction.cc
@@ -17,6 +17,7 @@
 #include "dex_instruction.h"
 
 #include "dex_file.h"
+#include "utils.h"
 #include <iomanip>
 
 namespace art {