Migrate counter to use locked int

src/counter.c

@@ -6,18 +6,12 @@
 
 bool
 counter_accum_init(counter_accum_t *counter, uint64_t interval) {
-#ifndef JEMALLOC_ATOMIC_U64
-	if (malloc_mutex_init(&counter->mtx, "counter_accum",
+	if (LOCKEDINT_MTX_INIT(counter->mtx, "counter_accum",
 	    WITNESS_RANK_COUNTER_ACCUM, malloc_mutex_rank_exclusive)) {
 		return true;
 	}
-	counter->accumbytes = 0;
-#else
-	atomic_store_u64(&counter->accumbytes, 0,
-	    ATOMIC_RELAXED);
-#endif
+	locked_init_u64_unsynchronized(&counter->accumbytes, 0);
 	counter->interval = interval;
-
 	return false;
 }