[SPARK-4527][SQl]Add BroadcastNestedLoopJoin operator selection testsuite

In `JoinSuite` add BroadcastNestedLoopJoin operator selection testsuite

Author: wangxiaojing <u9jing@gmail.com>

Closes #3395 from wangxiaojing/SPARK-4527 and squashes the following commits:

ea0e495 [wangxiaojing] change style
53c3952 [wangxiaojing] Add BroadcastNestedLoopJoin operator selection testsuite