质疑CLR Via C#中的一段代码，求指教狠批，只要能求得答案！解决方案

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Collections;

namespace GenericsTest
{
    sealed class Program
    {
        static void Main(string[] args)
        {
            ValueTypePerfTest();
            ReferenceTypePerfTest();
            Console.ReadKey();
        }

        private static void ValueTypePerfTest()
        {
            const int count = 10000000;
            using (new OperationTimer("List<Int32>"))
            {
                List<Int32> l = new List<int>(count);
                for (Int32 n = 0; n < count; n++)
                {
                    l.Add(n);
                    Int32 x = l[n];
                }
                l = null;

            }

            using (new OperationTimer("ArrayList of Int32"))
            {
                ArrayList a = new ArrayList();
                for (Int32 n = 0; n < count; n++)
                {
                    a.Add(n);
                    Int32 x = (Int32)a[n];
                }
                a = null;
            }
        }

        private static void ReferenceTypePerfTest()
        {
            const int count = 10000000;
            using (new OperationTimer("List<String>"))
            {
                List<string> l = new List<string>();
                for (Int32 i = 0; i < count; i++)
                {
                    l.Add("X");
                    String x = (String)l[i];
                }
                l = null;
            }
            using (new OperationTimer("ArrayList Of  String"))
            {
                ArrayList a = new ArrayList();
                for (Int32 i = 0; i < count; i++)
                {
                    a.Add("X");
                    String x = (String)a[i];
                }
                a = null;
            }

        }
    }


    internal sealed class OperationTimer : IDisposable
    {
        public void Dispose()
        {
            Console.WriteLine("{0:###0.00000000} 秒, (GCS={1}) {2}", (Stopwatch.GetTimestamp() - m_startTime) / (double)Stopwatch.Frequency, GC.CollectionCount(0) - m_collectionCount, m_text);
        }

        private Int64 m_startTime;
        private String m_text;
        private Int32 m_collectionCount;
        public OperationTimer(String text)
        {
            PrepareForOperation();
            m_text = text;
            m_collectionCount = GC.CollectionCount(0);
            m_startTime = Stopwatch.GetTimestamp();

        }

        private static void PrepareForOperation()
        {
            GC.Collect();
           【 GC.WaitForPendingFinalizers();
            GC.Collect();】
        }
    }
}

GC.WaitForPendingFinalizers();