[skip ci] Remove unused outdated .circleci bazel_definitions file (#71943)
Summary:
Small clean-up, realized this file isn't necessary after migrating to GHA, so removing this file
Pull Request resolved: https://github.com/pytorch/pytorch/pull/71943
Test Plan: running .circleci/regenerate.sh yields no config changes
Reviewed By: malfet
Differential Revision: D33901182
Pulled By: janeyx99
fbshipit-source-id: e8ff16395c81be25dae5b84619c6b4bfe749ada2
(cherry picked from commit e564c1ed5e2b23db537c25f9312647f13a10ab15)
