flatten_single_dir renames a tree extracted seconds earlier, while
Defender or another scanner still holds it, and ffmpeg/agent-browser
installs died on the package/bin rename with [WinError 5] (#131884).
The entry displace/restore renames in install.py had the same bare call.
pm.filesystem.retry_held retries EACCES/EPERM/EBUSY for about 3s and
raises anything else immediately; the hoist, merge_tree and the entry
swaps use it.
Co-authored-by: bighamx <10262931+bighamx@users.noreply.github.com>
Co-authored-by: lzmuhioin <1814826+lzmuhioin@users.noreply.github.com>