Canonicalize includes in c10, and add tests for it (#36299)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/36299
Test Plan: Imported from OSS
Differential Revision: D20943005
Pulled By: ezyang
fbshipit-source-id: 9dd0a58824bd0f1b5ad259942f92954ba1f63eae
