If we fail to find a member when extracting a directory, try adding a trailing
slash to the member name. In certain cases, the member in the tarfile will
contain a trailing slash but the file name in FILES.json will never contain
the trailing slash.
If unable to find the member, handle the KeyError and print a nicer error.
Also check if a directory exists before creating it since it may have been
extracted from the archive.
Fixes#70009
* Add unit tests
* Use loop for trying to get members
