gh-129210: Skip second reachability check in ft GC if no finalizers run

As for the regular GIL garbage collector, skip the second reachability check if
no objects to-be-collected have finalizers, and hence none can be resurrected.

In (so far very limited) testing this gives a ~10% overall performance
improvement to the motivating benchmark's runtime and a ~35% improvement to its
reported time.

The pyperformance gc_traversal and gc_collect benchmarks show no significant
difference and a 6% improvement respectively.

Author: duaneg

Python/gc_free_threading.c

@@ -1593,22 +1593,25 @@ debug_cycle(const char *msg, PyObject *op)
  * Note that this may remove some (or even all) of the objects from the
  * list, due to refcounts falling to 0.
  */
-static void
+static int
 finalize_garbage(struct collection_state *state)
 {
     // NOTE: the unreachable worklist holds a strong reference to the object
     // to prevent it from being deallocated while we are holding on to it.
+    int finalizer_run = 0;
     PyObject *op;
     WORKSTACK_FOR_EACH(&state->unreachable, op) {
         if (!_PyGC_FINALIZED(op)) {
             destructor finalize = Py_TYPE(op)->tp_finalize;
             if (finalize != NULL) {
                 _PyGC_SET_FINALIZED(op);
                 finalize(op);
+                finalizer_run = 1;
                 assert(!_PyErr_Occurred(_PyThreadState_GET()));
             }
         }
     }
+    return finalizer_run;
 }
 
 // Break reference cycles by clearing the containers involved.
@@ -2009,11 +2012,13 @@ gc_collect_internal(PyInterpreterState *interp, struct collection_state *state,
     // Call weakref callbacks and finalizers after unpausing other threads to
     // avoid potential deadlocks.
     call_weakref_callbacks(state);
-    finalize_garbage(state);
+    int check_resurrected = finalize_garbage(state);
 
-    // Handle any objects that may have resurrected after the finalization.
     _PyEval_StopTheWorld(interp);
-    err = handle_resurrected_objects(state);
+    // Handle any objects that may have resurrected after finalization, if any
+    if (check_resurrected) {
+        err = handle_resurrected_objects(state);
+    }
     // Clear free lists in all threads
     _PyGC_ClearAllFreeLists(interp);
     _PyEval_StartTheWorld(interp);