ART: Clean up art_field.h

Clean up the header. Fix up other headers including the -inl file,
in an effort to prune the include graph. Fix broken transitive
includes by making includes explicit.

Test: m
Change-Id: I6ff2d6f89b741d8188e19426eccf4743fec688fc
diff --git a/imgdiag/imgdiag.cc b/imgdiag/imgdiag.cc
index f307cbc..06a0f23 100644
--- a/imgdiag/imgdiag.cc
+++ b/imgdiag/imgdiag.cc
@@ -28,6 +28,7 @@
 
 #include "android-base/stringprintf.h"
 
+#include "art_field-inl.h"
 #include "art_method-inl.h"
 #include "base/unix_file/fd_file.h"
 #include "gc/space/image_space.h"