[SPARK-18873][SQL][TEST] New test cases for scalar subquery (part 2 of 2) -...

[SPARK-18873][SQL][TEST] New test cases for scalar subquery (part 2 of 2) - scalar subquery in predicate context

## What changes were proposed in this pull request?
This PR adds new test cases for scalar subquery in predicate context

## How was this patch tested?
The test result is compared with the result run from another SQL engine (in this case is IBM DB2). If the result are equivalent, we assume the result is correct.

Author: Nattavut Sutyanyong <nsy.can@gmail.com>

Closes #16798 from nsyca/18873-2.