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/class_table-inl.h b/runtime/class_table-inl.h
index 35fce40..b15d82f 100644
--- a/runtime/class_table-inl.h
+++ b/runtime/class_table-inl.h
@@ -18,6 +18,8 @@
 #define ART_RUNTIME_CLASS_TABLE_INL_H_
 
 #include "class_table.h"
+
+#include "gc_root-inl.h"
 #include "oat_file.h"
 
 namespace art {