What is the purpose of the change

Currently, BatchMessage might be compressed like a normal Message (when it's size reached the point), and this compressing action will cause an sending error:

[2019-Sep-20 14:07:20.254324](error):processSendResponse error remark:java.lang.ArrayIndexOutOfBoundsException, java.util.zip.CRC32.update(CRC32.java:74), error code:1[processSendResponse:537]
[2019-Sep-20 14:07:20.254504](error):send error[sendMessageSync:381]
[2019-Sep-20 14:07:20.254706](error):msg: response is null,error:-1,in file </fakepath/rocketmq-client-cpp/src/MQClientAPIImpl.cpp> line:384[send:147]

Brief changelog

1. Align to JAVA SDK: Skip compressing if message is a batch one. (You can refer to apache/rocketmq )

Verifying this change

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