Unset flzr_can_work before doing the work

reclaim.c

@@ -893,11 +893,9 @@ static void* init_finalize_thread(void *arg)
     while (flzr_can_work == 0) {
       pthread_cond_wait(&flzr_t_has_work, &flzr_mtx);
     }
-    pthread_mutex_unlock(&flzr_mtx);
-    GC_invoke_finalizers();
-    pthread_mutex_lock(&flzr_mtx);
     flzr_can_work = 0;
     pthread_mutex_unlock(&flzr_mtx);
+    GC_invoke_finalizers();
   }
   return arg;
 }