Update lazy_ir.py from lazy_tensor_staging (#72730)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/72730
This diff contains changes from several PRs landed to lazy_tensor_staging branch.
- generating 'fallback' overrides for each codegenned op, useful for debugging
- supports operators which are missing aten:: symbols for op names, instead using their string counterpart
- makes the IR class a base class instead of hardcoding the assumption of TS
Test Plan: tested on lazy_tensor_staging branch
Reviewed By: desertfire
Differential Revision: D34178476
fbshipit-source-id: 7190b2e0d82b4eb1f4510c858c24446c6df3f9d0
(cherry picked from commit 6713d3f0ef1bb0ea5e2acfad2ea252cf73d1cbbf)
