Move more Class annotations to native.

Art side of this change. There is also a corresponding Libcore change.

Seeing speedup in AnnotatedElementBenchmark.
GetDeclaredClasses	 21.61x
GetDeclaringClass	108.73x
GetEnclosingClass	 87.81x
GetEnclosingConstructor	 23.35x
GetEnclosingMethod	 22.71x
GetModifiers		152.47x
GetSimpleName		106.11x
IsAnonymousClass	 91.28x
IsLocalClass		 51.95x

Change-Id: I2b7f7eb7785fc20671fd7c338ffa9c7048a44a48
diff --git a/runtime/native/java_lang_reflect_Method.cc b/runtime/native/java_lang_reflect_Method.cc
index 1219f85..caacba6 100644
--- a/runtime/native/java_lang_reflect_Method.cc
+++ b/runtime/native/java_lang_reflect_Method.cc
@@ -82,15 +82,18 @@
     mirror::ObjectArray<mirror::Class>* declared_exceptions = klass->GetThrows()->Get(throws_index);
     return soa.AddLocalReference<jobjectArray>(declared_exceptions->Clone(soa.Self()));
   } else {
-    mirror::ObjectArray<mirror::Object>* result_array =
+    mirror::ObjectArray<mirror::Class>* result_array =
         method->GetDexFile()->GetExceptionTypesForMethod(method);
     if (result_array == nullptr) {
       // Return an empty array instead of a null pointer
       mirror::Class* class_class = mirror::Class::GetJavaLangClass();
       mirror::Class* class_array_class =
           Runtime::Current()->GetClassLinker()->FindArrayClass(soa.Self(), &class_class);
-      mirror::ObjectArray<mirror::Object>* empty_array =
-          mirror::ObjectArray<mirror::Object>::Alloc(soa.Self(), class_array_class, 0);
+      if (class_array_class == nullptr) {
+        return nullptr;
+      }
+      mirror::ObjectArray<mirror::Class>* empty_array =
+          mirror::ObjectArray<mirror::Class>::Alloc(soa.Self(), class_array_class, 0);
       return soa.AddLocalReference<jobjectArray>(empty_array);
     } else {
       return soa.AddLocalReference<jobjectArray>(result_array);