Sync lazy_tensor_staging back to master (#72875)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/72875
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
It also resolves lint issues and in particular cleans up the following:
* {Type}s shouldn't be passed into isValueType, and using the catch-all base class of CType is nicer than specifying a list of types.
Fixes #72852
Test Plan: test manually on lazy_tensor_staging branch
Reviewed By: shunting314
Differential Revision: D34250357
fbshipit-source-id: aa7d589f605055d5d02bc77c77fa6f1182ff7497
(cherry picked from commit 2f8f5e49719027a309a9cddbc20a1bfb920276a8)
