Use UICommon's game list code on Android

Deduplicates code, and gets rid of some problems the old code had
(such as: bad performance when calling native functions, only one
disc showing up for multi-disc games, Wii banners being low-res,
unnecessarily much effort being needed for adding more metadata).

Source/Android/jni/AndroidCommon/IDCache.h

@@ -0,0 +1,23 @@
+// Copyright 2018 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <jni.h>
+
+namespace IDCache
+{
+JavaVM* GetJavaVM();
+
+jclass GetNativeLibraryClass();
+jmethodID GetDisplayAlertMsg();
+
+jclass GetGameFileClass();
+jfieldID GetGameFilePointer();
+jmethodID GetGameFileConstructor();
+
+jclass GetGameFileCacheClass();
+jfieldID GetGameFileCachePointer();
+
+}  // namespace IDCache