[NNAPI] Remove solid weights support (#47518)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/47518
This was left over from an old version of the code. The idea was that
instead of indexing into separate tensors for each weight, you could
bundle them all into a single file and use different offsets into that
file. With the current design, this is nontrivial to support, so drop
the code for now.
Test Plan: CI
Reviewed By: axitkhurana
Differential Revision: D25317935
Pulled By: dreiss
fbshipit-source-id: e26ab3a8d437cb1bbb50319209fa56d9c571ce61
