remove ONNX & Turn on `NO_API` for mobile build (#23546)
Summary:
### Summary
The iOS build was broken after this PR 👉 [23195](https://github.com/pytorch/pytorch/pull/23195/files) was merged, as there are two files still have dependency on ONNX.
- `test.cpp` in `test/cpp/jit`
- `export.cpp` in `torch/csrc/jit`
This PR is to remove ONNX completely from mobile build.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/23546
Test Plan:
- The `build_ios.sh` finished successfully.
- The `libtorch.a` can be compiled and run on iOS devices
Differential Revision: D16558236
Pulled By: xta0
fbshipit-source-id: b7ff1db750698cfd5a72d5cb0b9f2f378e315077
