ART: Small class-inl.h cleanup

Remove unnecessary class_linker-inl.h include, and fix up all
transitives (mainly gc_root-inl.h). Also clean up reference.h.

Test: m test-art-host
Change-Id: I47bd6edcfe4a23821e37a6e6fa8cca91d0d2d226
diff --git a/runtime/gc/space/dlmalloc_space.cc b/runtime/gc/space/dlmalloc_space.cc
index 9282ec7..7ec54f5 100644
--- a/runtime/gc/space/dlmalloc_space.cc
+++ b/runtime/gc/space/dlmalloc_space.cc
@@ -26,6 +26,7 @@
 #include "mirror/class-inl.h"
 #include "mirror/object-inl.h"
 #include "runtime.h"
+#include "scoped_thread_state_change-inl.h"
 #include "thread.h"
 #include "thread_list.h"
 #include "utils.h"