Remove redundant small int check in long_dealloc

[eendebakpt]

Feature or enhancement

Proposal:

The python small ints are immortal with a fixed reference count. For that reason these objects can never reach reference count zero and are never deallocated. We can remove the special casing in long_dealloc. For safety we replace the check with an assert.

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

No response

Linked PRs

• gh-127119: Remove check on accidental deallocation of immortal objects for free-threaded build #127120
• gh-127119: Faster check for small ints in long_dealloc #127620
• Draft: gh-127119: Faster check for small ints in long_dealloc (debug) #128187