Add AccessibleObject and Field to mirror

Main motivation is to remove all the functionality / field access on
java side to ArtField. Also comes with some reflection speedups /
slowdowns.

Summary results:
getDeclaredField/getField are slower mostly due to JNI overhead.
However, there is a large speedup in getInt, setInt,
GetInstanceField, and GetStaticField.

Before timings (N5 --compiler-filter=everything):

                       benchmark      ns linear runtime
          Class_getDeclaredField  782.86 ===
                  Class_getField  832.77 ===
                    Field_getInt  160.17 =
                    Field_setInt  195.88 =
                GetInstanceField 3214.38 ==============
                  GetStaticField 6809.49 ==============================

After:
          Class_getDeclaredField 1068.15 ============
                  Class_getField 1180.00 ==============
                    Field_getInt  121.85 =
                    Field_setInt  139.98 =
                GetInstanceField 1986.15 =======================
                  GetStaticField 2523.63 ==============================

Bug: 19264997

Change-Id: Ic0d0fc1b56b95cd6d60f8e76f19caeaa23045c77
diff --git a/runtime/mirror/reference.h b/runtime/mirror/reference.h
index 7345448..69ef69c 100644
--- a/runtime/mirror/reference.h
+++ b/runtime/mirror/reference.h
@@ -99,7 +99,7 @@
     return java_lang_ref_Reference_.Read<kReadBarrierOption>();
   }
   static void SetClass(Class* klass);
-  static void ResetClass(void);
+  static void ResetClass();
   static void VisitRoots(RootCallback* callback, void* arg);
 
  private: