Land code coverage tool for OSS (#43778)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/43778
Move code_coverage_tool from experimental folder to caffe2/tools folder.
Delete `TODO` and fb-related code.
Test Plan: Test locally
Reviewed By: malfet
Differential Revision: D23399983
fbshipit-source-id: 92316fd3cc88409d087d2dc6ed0be674155b3762
Author
yujunzhao@devvm229.ftw0.facebook.com
