Add get_native_lib that is used by iwasm to load wasi-nn as a native library

[rodjjo]

What

• When it was running the example from wasm-micro-runtime/core/iwasm/libraries/wasi-nn there was an error where iwasm was not able to register the functions into the wasm vm.
• Fix a typo in core/iwasm/libraries/wasi-nn/test/utils.c

Why

We need get_native_lib in order to use --native-lib=path-to-lib.so missing for this wasi-nn library.

Note

I kept get_wasi_nn_export_apis as it was as i did not know where it is used.

Now it runs:

[rodjjo]

I guess we have an unstable test there. I just included a empty line (I would never affect the tests).

[wenyongh]

I guess we have an unstable test there. I just included a empty line (I would never affect the tests).

Yes, the CI sometimes encounters error, e.g. failed to download packages. I re-ran it and now it works.

[wenyongh]

LGTM

[lum1n0us]

Please test with #3820

By design, --native-lib is not required.

[lum1n0us]

Please test with #3820

Refer to core/iwasm/libraries/wasi-nn/README.md in #3820

[rodjjo]

@lum1n0us I made questions/suggestions on your PR.
I'm closing this one due your changes there.