ART: Clean up includes.

Reduce dependencies to improve incremental build times.
Break up circular dependency involving class_linker-inl.h.

Change-Id: I4be742c5c2b5cd9855beea86630fd68aab76b0db
diff --git a/runtime/transaction_test.cc b/runtime/transaction_test.cc
index 9792eca..aee2c54 100644
--- a/runtime/transaction_test.cc
+++ b/runtime/transaction_test.cc
@@ -17,6 +17,7 @@
 #include "transaction.h"
 
 #include "art_field-inl.h"
+#include "class_linker-inl.h"
 #include "common_runtime_test.h"
 #include "mirror/array-inl.h"
 #include "mirror/art_method-inl.h"