Mention withCredentials attribute in the error message about CORS check failure

third_party/WebKit/LayoutTests/http/tests/eventsource/eventsource-cors-with-credentials-expected.txt

-CONSOLE ERROR: EventSource cannot load http://127.0.0.1:8080/eventsource/resources/es-cors-credentials.php?count=1. A wildcard '*' cannot be used in the 'Access-Control-Allow-Origin' header when the credentials flag is true. Origin 'http://127.0.0.1:8000' is therefore not allowed access.
-CONSOLE ERROR: EventSource cannot load http://127.0.0.1:8080/eventsource/resources/es-cors-credentials.php?count=2. A wildcard '*' cannot be used in the 'Access-Control-Allow-Origin' header when the credentials flag is true. Origin 'http://127.0.0.1:8000' is therefore not allowed access.
-CONSOLE ERROR: EventSource cannot load http://127.0.0.1:8080/eventsource/resources/es-cors-credentials.php?count=3. Credentials flag is 'true', but the 'Access-Control-Allow-Credentials' header is ''. It must be 'true' to allow credentials. Origin 'http://127.0.0.1:8000' is therefore not allowed access.
+CONSOLE ERROR: EventSource cannot load http://127.0.0.1:8080/eventsource/resources/es-cors-credentials.php?count=1. The value of the 'Access-Control-Allow-Origin' header in the response must not be the wildcard '*' when the request's credentials mode is 'include'. Origin 'http://127.0.0.1:8000' is therefore not allowed access.
+CONSOLE ERROR: EventSource cannot load http://127.0.0.1:8080/eventsource/resources/es-cors-credentials.php?count=2. The value of the 'Access-Control-Allow-Origin' header in the response must not be the wildcard '*' when the request's credentials mode is 'include'. Origin 'http://127.0.0.1:8000' is therefore not allowed access.
+CONSOLE ERROR: EventSource cannot load http://127.0.0.1:8080/eventsource/resources/es-cors-credentials.php?count=3. The value of the 'Access-Control-Allow-Credentials' header in the response is '' which must be 'true' when the request's credentials mode is 'include'. Origin 'http://127.0.0.1:8000' is therefore not allowed access.
 Test that EventSource cross-origin requests with credentials fail until the correct CORS headers are sent.
 
 On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
 
 
 PASS es = new EventSource("http://127.0.0.1:8080/eventsource/resources/es-cors-credentials.php?count=1", {'withCredentials': true}) did not throw exception.
 PASS es.withCredentials is true
 PASS count != 4 && count != 5 is true
 PASS es = new EventSource("http://127.0.0.1:8080/eventsource/resources/es-cors-credentials.php?count=2", {'withCredentials': true}) did not throw exception.
 PASS es.withCredentials is true
 PASS count != 4 && count != 5 is true
 PASS es = new EventSource("http://127.0.0.1:8080/eventsource/resources/es-cors-credentials.php?count=3", {'withCredentials': true}) did not throw exception.
 PASS es.withCredentials is true
 PASS count != 4 && count != 5 is true
 PASS es = new EventSource("http://127.0.0.1:8080/eventsource/resources/es-cors-credentials.php?count=4", {'withCredentials': true}) did not throw exception.
 PASS es.withCredentials is true
 PASS evt.origin.indexOf('http://127.0.0.1:8080') === 0 is true
 PASS evt.data is "DATA1"
 PASS evt.lastEventId is "77"
 PASS count is 5
 PASS evt.origin.indexOf('http://127.0.0.1:8080') === 0 is true
 PASS count is 5
 PASS evt.data is "DATA2"
 PASS successfullyParsed is true
 
 TEST COMPLETE