gh-121267: Improve performance of tarfile (#121267) (#121269)

Tarfile in the default write mode spends much of its time resolving UIDs
into usernames and GIDs into group names. By caching these mappings, a
significant speedup can be achieved.

In my simple benchmark[1], this extra caching speeds up tarfile by 8x.

[1] https://gist.github.com/jforberg/86af759c796199740c31547ae828aef2

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Co-authored-by: Tian Gao <gaogaotiantian@hotmail.com>
Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
Co-authored-by: Shantanu <12621235+hauntsaninja@users.noreply.github.com>