[3.13] gh-143638: Forbid cuncurrent use of the Pickler and Unpickler objects in C implementation (GH-143664) (GH-143687)

Previously, this could cause crash or data corruption, now concurrent calls
of methods of the same object raise RuntimeError.
(cherry picked from commit d1282efb2b847bf9274d78c5f15ea00499b2c894)