Remove useless pull consumer example.

[ShannonDing]

just remove PullConsumerTest.java file.
https://github.com/apache/rocketmq/blob/develop/example/src/main/java/org/apache/rocketmq/example/simple/PullConsumerTest.java

[azhsmesos]

please assigned it to me, i want to try it.

[ShannonDing]

please assigned it to me, i want to try it.

welcome.

[azhsmesos]

please assigned it to me, i want to try it.

welcome.

#5137 it's my pull request