Add unit tests for additionalPeroperties keyword in schema validation

:Release Notes:
Added unit tests to check additionalPeroperties keyword usage during
schema validation

:Detailed Notes:

:Testing Performed:
Unit tests succeeded

:QA Notes:

:Issues Addressed:
[GF-9795] Write unit tests for schema validator

Open-webOS-DCO-1.0-Signed-off-by: Mykola Kryvonos <mykola.kryvonos@lge.com>

Change-Id: Ib86f34f5519ee25b14370839afd9483237a23b2b
Reviewed-on: https://g2g.palm.com/3076
Reviewed-by: Build Verification
Reviewed-by: Mykola Kryvonos <mykola.kryvonos@lge.com>
Tested-by: Mykola Kryvonos <mykola.kryvonos@lge.com>
Reviewed-by: Anatolii Sakhnik <anatolii.sakhnik@lge.com>
Reviewed-by: Alekseyev Oleksandr <alekseyev.oleksandr@lge.com>
Tested-by: Alekseyev Oleksandr <alekseyev.oleksandr@lge.com>