[webapi] Add 2 TCs and delete duplicated files in tct-webstorage-w3c-tests

Impacted Suites: tct-webstorage-w3c-tests
Impacted TCs num: New 2, Update 0, Delete 16
Unit test platform: IVI
IVI test result summary: Pass 2, Fail 0, Blocked 0

Add Reason:
Add 2 TCs for missing test point.

Delete Reason:
These cases no reference and have been covered by the exist cases