run-perf-tests should report server-side errors

run-perf-tests should report server-side errors
https://bugs.webkit.org/show_bug.cgi?id=76802

Reviewed by Tony Chang.

Report errors whenever server's response doesn't match "OK".

* Scripts/webkitpy/common/net/file_uploader.py:
(FileUploader.upload_single_text_file):
(FileUploader.upload_as_multipart_form_data):
(FileUploader._upload_data.callback):
(FileUploader):
(FileUploader._upload_data):
* Scripts/webkitpy/performance_tests/perftestsrunner.py:
(PerfTestsRunner._upload_json):
* Scripts/webkitpy/performance_tests/perftestsrunner_unittest.py:
(test_upload_json):
(test_upload_json.MockFileUploader.upload_single_text_file):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@105650 268f45cc-cd09-0410-ab3c-d52691b4dbfc