Move JNI_OnLoad to separate file which registers both fbjni and jni methods

Summary: Move JNI_ONLoad to a separate file so that both fbjni native methods and vanillla jni native methods can be initialized correctly

Reviewed By: amir-shalem

Differential Revision: D17840166

fbshipit-source-id: 045df0df7a95bc331cbbefb3a118a349f3029465

java/jni/yogajni.h

@@ -0,0 +1,11 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+#include <fbjni/fbjni.h>
+
+namespace YGJNI {
+jint registerNativeMethods(JavaVM* vm);
+};