Remove the dependence on jsonp from more of new-run-webkit-tests and the test results...

Remove the dependence on jsonp from more of new-run-webkit-tests and the test results server
https://bugs.webkit.org/show_bug.cgi?id=72813

Reviewed by Adam Barth.

Once this lands, we can start storing pure json in the test results server and then
we can delete the code with all the FIXMEs added here.

* Scripts/webkitpy/layout_tests/controllers/manager.py:
* Scripts/webkitpy/layout_tests/layout_package/json_results_generator.py:
Only add jsonp for full_results.json.
* TestResultServer/model/jsonresults.py:
* TestResultServer/model/jsonresults_unittest.py:
Accept pure json uploads.
* TestResultServer/static-dashboards/dashboard_base.js:
(appendJSONScriptElementFor):
Use the callback parameter so that the server can start returning pure json if it's left out.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@100862 268f45cc-cd09-0410-ab3c-d52691b4dbfc