[cordova|misc|stability|webapi|wrt] Update testharness to latest

- Update testharness to latest version
  https://github.com/w3c/testharness.js (commit 2486f01bf4c58de1c1b7cb39322af7b55c6c700b)
- Add copy.py
[usecase] Move CSSStyleAttribute to usecase-webapi-xwalk-tests

- usecase-webapi-w3c-tests have been renamed to usecase-webapi-xwalk-tests, move CSSStyleAttribute to there
[cordova|misc|stability|webapi|wrt] Update webrunner

https://github.com/testkit/webrunner (commit 9e01616dbf2d565fcd18032f5685f0e74c455ae8)

- Change the license to BSD
- Replace tab with two whitespaces
- Remove executable mode
Merge pull request #1366 from haoxli/update-testharness

[cordova|misc|stability|webapi|wrt] Update testharness to latest
Merge pull request #1367 from haoxli/update-webrunner

[cordova|misc|stability|webapi|wrt] Update webrunner
Merge pull request #1368 from haoxli/usecase/move-cssstyle

[usecase] Move CSSStyleAttribute to usecase-webapi-xwalk-tests
[webapi][XWALK-2955] Update two reference files

Because reference file using png image(support/1x1-green.png) as background does not match test case background color of css style.
Impacted tests(approved):new 0,update 17,delete 0
Unit test platform:[TizenIVI]
Unit test result summary:pass 17,fail 0,block 0
Merge pull request #1318 from chenxix/webapi/reapir-background

[webapi][XWALK-2955] Update two reference files