Added few regression tests for JArray

[GF-3349] Libpbnjson: examine and fix JValue::operator==

Open-webOS-DCO-1.0-Signed-off-by: Anatolii Sakhnik <asakhnik@luxoft.com>

Change-Id: I426e9f4bec9238ab45b77c1b077db023b5db58a6