Add a xnnpack partitioner flag to dump XNNGraph AOT

[digantdesai]

🚀 The feature, motivation and pitch

This is essential for any deeper debugging beyond the surface level. This is something we have been asked multiple times for anyone doing serious model development work.

Alternatives

None.

Additional context

When serializing XNNGraph in the partitioner, we already have this information as json. This optional flag will dump it in a file, for further debugging.

RFC (Optional)

None

[mcr229]

should this be a discussion instead of an issue?

[digantdesai]

More like a feature req?

[mcr229]

hmm should feature req be discussions or issues? idk haha