[BE] Remove unused files and dead code (#1913)

Author: atalman

.circleci/scripts/binary_checkout.sh

@@ -144,7 +144,6 @@ export BUILD_JNI=$BUILD_JNI
 export PIP_UPLOAD_FOLDER="$PIP_UPLOAD_FOLDER"
 export DOCKER_IMAGE="$DOCKER_IMAGE"
 
-# Remove WORKD_DIR, PYTORCH_ROOT, BUILDER_ROOT defined & persisted in binary_checkout.sh
 export MAC_PACKAGE_WORK_DIR="$WORK_DIR"
 export MINICONDA_ROOT="$WORK_DIR/miniconda"
 export PYTORCH_FINAL_PACKAGE_DIR="$WORK_DIR/final_pkgs"