Switch py_utils import to pathlib. os.stat path before adding just to catch future copy-paste mistakes. Bug: angleproject:6854 Change-Id: If58c46f99aca93e6aeda90a987ceebbbb1b66955 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3600911 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Roman Lavrov <romanl@google.com>