Message 379691 - Python tracker

In bpo-38858, I made the small integer singletons per interpreter: commit 630c8df5cf126594f8c1c4579c1888ca80a29d59. _PyLong_Zero and _PyLong_One variables are still shared by all interpreters, whereas subinterpreters must not share Python objects: see bpo-40533.

I propose to add new _PyLong_GetZero() and _PyLong_GetOne() functions to replace _PyLong_Zero and _PyLong_One variables. These functions will retrieve the singletons from tstate->interp->small_ints.