GrinderUtils.getThreadUniqId() is not working in IntelliJ Context

[junoyoon]

Currently GrinderUtils.getThreadUniqId() which is used to get the uniq id for current thread is not working correctly due to the grinder properties is null in IntelliJ Context.
It blocks the use of this utility when making the script using IDE.

We have to make it just return 0 when it's in IntelliJ.

[junoyoon]

Fixed