[webapi][XWALK-3189] Remove 2 cases for CSP

- Due to these 2 case need be written, so remove firstly.

Impacted TCs num: New 0, Update 0, Delete 2
Unit test Platform: [Tizen-IVI]
Unit test result summary: Pass 0, Fail 0, Blocked 0
[ivi-tct][XWALK-3204] Delete the duplicated case ID

- Delete the duplicated case ID background-002.
[ivi-tct] Format tests.xml and tests.full.xml

- Format tests.xml by "xmllint --format tests.xml"
- Format tests.full.xml by "xmllint --format tests.full.xml"
Merge pull request #1523 from JianfengXu/tct/csp/3189

[webapi][XWALK-3189] Remove 2 cases for CSP
Merge pull request #1522 from chenxix/webapi/modify-background-ivi-tct

[ivi-tct][XWALK-3204] Delete the duplicated case ID