pytorch

f06d3904 - Land `code_coverage_tool` to `caffe2/tools` folder

Land `code_coverage_tool` to `caffe2/tools` folder Summary: Move `code_coverage_tool` from `experimental` folder to `caffe2/tools` folder. Not sure if the fb related code is something we don't want to share with the oss. Can reviewers please help me check with `fbcode_coverage.py` and files in `fbcode/` folder? Test Plan: Test locally Reviewed By: malfet Differential Revision: D23379383 fbshipit-source-id: f6782389ebb1b147eaf6d3664b5955db79d24ff3