Add API for unexecuted op (#43629)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/43629
We have a few places where we count the size a block / subgraph - it's nice to have a shared API to ignore operators that are not executed in the optimized graph (will be used when i add a new profiling node in PR ^^)
Test Plan: Imported from OSS
Reviewed By: bertmaher
Differential Revision: D23358807
Pulled By: eellison
fbshipit-source-id: 62c745d9025de94bdafd9f748f7c5a8574cace3f
