Reapply "Delete TorchScript based Android demo app and point to ExecuTorch (#153633)" (#153656)

This reverts commit ae0e8f0c7316addab3f415dc767a9d34f58b0dae.

Keep android/libs/fbjni because it's being used by other components of
PyTorch.

Pull Request resolved: https://github.com/pytorch/pytorch/pull/153656
Approved by: https://github.com/malfet

android/pytorch_android/generate_test_asset.cpp

@@ -1,20 +0,0 @@
-#include <torch/csrc/jit/api/module.h>
-#include <torch/jit.h>
-#include <torch/script.h>
-
-#include <fstream>
-#include <iostream>
-#include <string>
-
-int main(int argc, char* argv[]) {
-  std::string input_file_path{argv[1]};
-  std::string output_file_path{argv[2]};
-
-  std::ifstream ifs(input_file_path);
-  std::stringstream buffer;
-  buffer << ifs.rdbuf();
-  torch::jit::Module m("TestModule");
-
-  m.define(buffer.str());
-  m.save(output_file_path);
-}