Fix object allocation counters in compaction

When we move an object in compaction, we do not decrement the total_freed_objects
of the original size pool or increment the total_allocated_objects of the
new size pool. This means that when this object dies, it will appear as
if the object was never freed from the original size pool and the new
size pool will have one more free than expected. This means that the new
size pool could appear to have a negative number of live objects.

gc/default.c

@@ -2636,7 +2636,10 @@ newobj_alloc(rb_objspace_t *objspace, rb_ractor_newobj_cache_t *cache, size_t si
         obj = newobj_cache_miss(objspace, cache, size_pool_idx, vm_locked);
     }
 
-    size_pools[size_pool_idx].total_allocated_objects++;
+    rb_size_pool_t *size_pool = &size_pools[size_pool_idx];
+    size_pool->total_allocated_objects++;
+    GC_ASSERT(SIZE_POOL_EDEN_HEAP(size_pool)->total_slots + SIZE_POOL_TOMB_HEAP(size_pool)->total_slots >=
+        (size_pool->total_allocated_objects - size_pool->total_freed_objects - size_pool->final_slots_count));
 
     return obj;
 }
@@ -7284,6 +7287,9 @@ gc_move(rb_objspace_t *objspace, VALUE src, VALUE dest, size_t src_slot_size, si
     RMOVED(src)->destination = dest;
     GC_ASSERT(BUILTIN_TYPE(dest) != T_NONE);
 
+    GET_HEAP_PAGE(src)->size_pool->total_freed_objects++;
+    GET_HEAP_PAGE(dest)->size_pool->total_allocated_objects++;
+
     return src;
 }