Merge "Don't fail if default namespace isn't found"

// "default" always exists.

Result<NativeLoaderNamespace> NativeLoaderNamespace::GetPlatformNamespace(bool is_bridged) {

  auto ns = GetExportedNamespace(kPlatformNamespaceName, is_bridged);

  if (!ns) {

  if (ns) return ns;

  ns = GetExportedNamespace(kDefaultNamespaceName, is_bridged);

  if (ns) return ns;

  // If nothing is found, return NativeLoaderNamespace constructed from nullptr.

  // nullptr also means default namespace to the linker.

  if (!is_bridged) {

    return NativeLoaderNamespace(kDefaultNamespaceName, static_cast<android_namespace_t*>(nullptr));

  } else {

    return NativeLoaderNamespace(kDefaultNamespaceName,

                                 static_cast<native_bridge_namespace_t*>(nullptr));

  }

  return ns;

}

Result<NativeLoaderNamespace> NativeLoaderNamespace::Create(