[1/N] Nnapi backend execute and compile (#62272)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/62272
Added Android NNAPI delegate implementation of runtime initialization (compilation) and execution.
The delegate's preprocess step was [previously implemented](https://github.com/pytorch/pytorch/pull/62225). Now, the reset of the delegate, which implements client-side execution, is added.
**nnapi_backend_lib.cpp**:
Implementation of delegate's compile and execute.
`execute()` is essentially a C++ implementation of [`NnapiModule`](https://github.com/pytorch/pytorch/blob/master/torch/backends/_nnapi/prepare.py), which wraps an NNAPI Compilation and handles preparation of weights, inputs, and outputs.
- Any steps that can be done before execution are moved to `compile()`.
- `init()` cannot be moved to `compile()` because it requires real inputs for dynamic shaping.
- `shape_compute_module` cannot currently be deserialized in `compile()`, since mobile::Module has no IValue conversion.
- Processed arguments that are modified by `init()` must be kept as member variables. Any other processed arguments are passed through a dictionary, `handles`.
**nnapi_bind.cpp & nnapi_bind.h**:
Created a header file for `nnapi_bind.cpp`, so that it's NnapiCompilation class can be used by `nnapi_backend_lib.cpp`.
**test_backend_nnapi.py**:
Enabled execution testing.
ghstack-source-id: 135432844
Test Plan:
Imported from OSS
Tested on devserver.
1. Load and unpack a special devserver build of NNAPI: `jf download GICWmAAzUR0eo20TAPasVts8ObhobsIXAAAz --file "nnapi-host-linux.tar.xz"`
2. `export LIBNEURALNETWORKS_PATH=/path/to/libneuralnetworks.so`
3. Run unittests: `python test/test_jit.py TestNnapiBackend` and `python test/test_nnapi.py`
TODO: test with lite interpreter runtime
Reviewed By: raziel, iseeyuan
Differential Revision: D29944873
fbshipit-source-id: 48967d873e79ef2cce9bcba2aeea3c52f7a18c07
