Revert "AssetManager cookies should be int32_t and not void*."

This reverts commit 95fcbf08f39f3ed3c5e9d1494a00721ddd7eaf11.

causes error: prototype for 'int32_t android::AssetManager::nextAssetPath(const int32_t*) const' does not match any in class 'android::AssetManager' and others

Change-Id: Icc65cf38f9119b456b69874bbcd26225bff81315