[webapi] [TC-1813]Add 1 P1 test for Locale API

Impacted tests(approved): new 1, update 0, delete 0
Unit test platform: [IVI]
Unit test summary: pass 1, fail 0, block 0
The API implemented is not compliant to this spec, please use https://bugs.tizen.org/jira/browse/TC-1813

Anyway it is a minor.