optimize performance : Hessian2Input.readObject() for 'B' or 'b'

[chjk]

这是一个对Hessian读取大byte[]的性能优化。读取耗时较优化前降低80%以上。

【优化原理】
原始读取逻辑：每次从流中读取256字节，然后处理后，放入一个新的ByteArrayOutputStream，如此循环后，最后再用ByteArrayOutputStream生成一个大的byte[]
本次优化：
1、对于只有一个chunk（总字节长度小于等于32768）的字节数组，不需要额外生成ByteArrayOutputStream了，而是直接读取chunk头上的字节长度，一次性生成固定长度的byte[]。然后将buffer中已经读取的一部分先写入到byte[]中，最后计算剩余应该从is流中读取的字节长度，使用_is.read(目标数组, 目标数组偏移量, 读取长度)的方法，一次性读取。
2、对于有多个chunk的字节数组，每个chunk使用上述步骤一次性读取，然后放入到ByteArrayOutputStream，多个chunk读取完成后，通过ByteArrayOutputStream输出拼接的byte[]

数据正确性测试：Hessian2InputTest.testSerialize()
简单的性能测试：Hessian2InputTest.testSerializeTime()

MacBook M1，测试结果如下：

单chunk的情况：反序列化byte[1024]， 10000次：
优化前：56ms
优化后：36ms

单chunk的情况：反序列化byte[10*1024]， 10000次：
优化前：312ms
优化后：40ms

单chunk的情况：反序列化byte[32000]， 10000次：
优化前：824ms （随字节长度线性增长）
优化后：54ms （几乎无增长）

多chunk的情况：反序列化byte[1024*1024]， 10000次：
优化前：24609ms
优化后：2225ms （降低90%）

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