Portable refactorings.

Separate quick from portable entrypoints.
Move architectural dependencies into arch.

Change-Id: I9adbc0a9782e2959fdc3308215f01e3107632b7c
diff --git a/runtime/entrypoints/quick/quick_throw_entrypoints.cc b/runtime/entrypoints/quick/quick_throw_entrypoints.cc
index 9588698..3bfa2f2 100644
--- a/runtime/entrypoints/quick/quick_throw_entrypoints.cc
+++ b/runtime/entrypoints/quick/quick_throw_entrypoints.cc
@@ -15,9 +15,9 @@
  */
 
 #include "callee_save_frame.h"
+#include "entrypoints/entrypoint_utils.h"
 #include "mirror/object.h"
 #include "object_utils.h"
-#include "runtime_support.h"
 #include "thread.h"
 #include "well_known_classes.h"