[3.5] bpo-39017: Avoid infinite loop in the tarfile module (GH-21454) (#21489)

Avoid infinite loop when reading specially crafted TAR files using the tarfile module
(CVE-2019-20907).
(cherry picked from commit 5a8d121a1f3ef5ad7c105ee378cc79a3eac0c7d4)

Co-authored-by: Rishi <rishi_devan@mail.com>