Support (un)squeeze in XNNPACK delegate via conversion to view

[GregoryComer]

Summary

This PR adds a new pass to the XNNPACK delegate to convert squeeze and unsqueeze nodes into views. These are then lowered to XNN static_reshape ops.

Note that this PR includes #7959, as it relies on lowering via view.

Test plan

Added test coverage at the pass and operator level under backends/xnnpack/test/ops/test_squeeze.py, backends/xnnpack/test/ops/test_unsqueeze.py, and backends/xnnpack/test/passes/test_convert_squeeze_to_view_pass.py.

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/7961

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✅ No Failures

As of commit d9c50c9 with merge base e78ed83 ():
💚 Looks good so far! There are no failures yet. 💚

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[github-actions]

Looks like this PR hasn't been updated in a while so we're going to go ahead and mark this as Stale.
Feel free to remove the Stale label if you feel this was a mistake.
If you are unable to remove the Stale label please contact a maintainer in order to do so.
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Stale pull requests will automatically be closed after 30 days of inactivity.