[3.13] gh-131719: add NULL pointer check to _PyMem_FreeDelayed (gh-131720) (gh-131722)

(cherry picked from commit 0a91456)

Co-authored-by: Tomasz Pytel <[email protected]>

Author: miss-islington

Misc/NEWS.d/next/Core_and_Builtins/2025-03-25-13-58-25.gh-issue-131719.zKv98a.rst

@@ -0,0 +1 @@
+Fix missing NULL check in ``_PyMem_FreeDelayed`` in :term:`free-threaded <free threading>` build.

Objects/obmalloc.c

@@ -1160,7 +1160,9 @@ void
 _PyMem_FreeDelayed(void *ptr)
 {
     assert(!((uintptr_t)ptr & 0x01));
-    free_delayed((uintptr_t)ptr);
+    if (ptr != NULL) {
+        free_delayed((uintptr_t)ptr);
+    }
 }
 
 void