[3.12] gh-107450: Check for overflow in the tokenizer and fix overflow test (GH-110832) (#110931)

(cherry picked from commit a1ac5590e0f8fe008e5562d22edab65d0c1c5507)

Co-authored-by: Lysandros Nikolaou <lisandrosnik@gmail.com>
Co-authored-by: Filipe Laíns <lains@riseup.net>
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>