[3.13] gh-100141: Allow pdb to deal with empty file (GH-125425) (#125536)

gh-100141: Allow pdb to deal with empty file (GH-125425)
(cherry picked from commit bb9604b62ae7f043594ffea9287f9213067cc7fb)

Co-authored-by: Tian Gao <gaogaotiantian@hotmail.com>