gh-94360: Fix a tokenizer crash when reading encoded files with syntax errors from stdin (GH-94386)

* gh-94360: Fix a tokenizer crash when reading encoded files with syntax errors from stdin

Signed-off-by: Pablo Galindo <pablogsal@gmail.com>

* nitty nit

Co-authored-by: Łukasz Langa <lukasz@langa.pl>
(cherry picked from commit 36fcde61)

Co-authored-by: Pablo Galindo Salgado <Pablogsal@gmail.com>