Add debug handle to xnnpack schema (#89033)
As title, add three things to the schema
1. debug handle for each node
2. file identifier, so we can sanity check we are getting the xnnpack schema flatbuffers file, instead of other random binary
3. extension, so the dumped binary will end up with its own extension like `myschema.xnnpack` (maybe can have a better name) instead of the default extension `.bin`
Differential Revision: [D40906970](https://our.internmc.facebook.com/intern/diff/D40906970/)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/89033
Approved by: https://github.com/mcr229
