This test suite comes from
https://github.com/w3c/web-platform-tests(commit 944356fc3e50ed67bd94895d43cf5212aba1594b)
with modification below:

eventsource-constructor-url-multi-window.htm
-          source = new self[0].EventSource("resources/message.php")
+          source = new self[0].EventSource("message.php")


These tests are copyright by W3C and/or the author listed in the test
file. The tests are dual-licensed under the W3C Test Suite License:
http://www.w3.org/Consortium/Legal/2008/04-testsuite-license
and the BSD 3-clause License:
http://www.w3.org/Consortium/Legal/2008/03-bsd-license
under W3C's test suite licensing policy:
http://www.w3.org/Consortium/Legal/2008/04-testsuite-copyright
