factor out jis_const

:Release Notes:

:Detailed Notes:

:Testing Performed:
unit-tests and performance test on desktop

:QA Notes:

:Issues Addressed:
[ANG-547] pbnjson: clash between error and null-value as result of jdom_parse

Open-webOS-DCO-1.0-Signed-off-by: Nikolay Orliuk <nikolay.orliuk@lge.com>
Change-Id: I100d2a67275ea902deea7189434dccfd4990a8e9
Reviewed-on: https://g2g.palm.com/4537
Reviewed-by: DCO Verification
Reviewed-by: Nikolay Orliuk <nikolay.orliuk@lge.com>
Tested-by: Nikolay Orliuk <nikolay.orliuk@lge.com>
Reviewed-by: Alexandr Smoktal <alexandr.smoktal@lge.com>
Reviewed-by: Anatolii Sakhnik <anatolii.sakhnik@lge.com>