Revert "Revert "Revert "Revert "Add intrinsic for Reference.get()""""

Fixed TargetReg issue causing build failure for x86.
This reverts commit 9e82bd3f0ce9e5f5777bea2f752ff3e251d32f9f.

Change-Id: I7e6a526954467aaf68deeed999880dfe9aa5f06e
diff --git a/runtime/mirror/reference-inl.h b/runtime/mirror/reference-inl.h
index 43767c8..b353402 100644
--- a/runtime/mirror/reference-inl.h
+++ b/runtime/mirror/reference-inl.h
@@ -22,6 +22,11 @@
 namespace art {
 namespace mirror {
 
+inline uint32_t Reference::ClassSize() {
+  uint32_t vtable_entries = Object::kVTableLength + 5;
+  return Class::ComputeClassSize(false, vtable_entries, 2, 0, 0);
+}
+
 inline bool Reference::IsEnqueuable() {
   // Not using volatile reads as an optimization since this is only called with all the mutators
   // suspended.