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/object.cc b/runtime/mirror/object.cc
index bbbdf98..57ac46f 100644
--- a/runtime/mirror/object.cc
+++ b/runtime/mirror/object.cc
@@ -214,7 +214,7 @@
         if (field->GetOffset().Int32Value() == field_offset.Int32Value()) {
           CHECK_NE(field->GetTypeAsPrimitiveType(), Primitive::kPrimNot);
           // TODO: resolve the field type for moving GC.
-          mirror::Class* field_type = field->GetType(!kMovingCollector);
+          mirror::Class* field_type = field->GetType<!kMovingCollector>();
           if (field_type != nullptr) {
             CHECK(field_type->IsAssignableFrom(new_value->GetClass()));
           }
@@ -236,7 +236,7 @@
         if (field->GetOffset().Int32Value() == field_offset.Int32Value()) {
           CHECK_NE(field->GetTypeAsPrimitiveType(), Primitive::kPrimNot);
           // TODO: resolve the field type for moving GC.
-          mirror::Class* field_type = field->GetType(!kMovingCollector);
+          mirror::Class* field_type = field->GetType<!kMovingCollector>();
           if (field_type != nullptr) {
             CHECK(field_type->IsAssignableFrom(new_value->GetClass()));
           }