Add unit test for JValue::hasKey

:Release Notes:

:Detailed Notes:
This commit is a partial implementation of the task: GF-6132 Create unit tests for JValue
It introduces commit for method JValue::hasKey

:Testing Performed:
Internal unit tests(including the new one)

:QA Notes:

:Issues Addressed:
[GF-6132] Create unit tests for JValue

Open-webOS-DCO-1.0-Signed-off-by: Alekseyev Oleksandr <alekseyev.oleksandr@lge.com>

Change-Id: I1fa5546747fc40b2ab6cc19bc8d584c0fe38ef0d
Reviewed-on: https://g2g.palm.com/2810
Reviewed-by: Build Verification
Reviewed-by: Alekseyev Oleksandr <alekseyev.oleksandr@lge.com>
Tested-by: Alekseyev Oleksandr <alekseyev.oleksandr@lge.com>
Reviewed-by: Anatolii Sakhnik <anatolii.sakhnik@lge.com>