Rework EventSource CORS tests to be usable from Workers.

LayoutTests/http/tests/eventsource/workers/eventsource-cors-redirect-expected.txt

Index: LayoutTests/http/tests/eventsource/workers/eventsource-cors-redirect-expected.txt
diff --git a/LayoutTests/http/tests/eventsource/workers/eventsource-cors-redirect-expected.txt b/LayoutTests/http/tests/eventsource/workers/eventsource-cors-redirect-expected.txt
new file mode 100644
index 0000000000000000000000000000000000000000..10bf757723dd024f98ec963a0502c67abaa67252
--- /dev/null
+++ b/LayoutTests/http/tests/eventsource/workers/eventsource-cors-redirect-expected.txt
@@ -0,0 +1,13 @@
+CONSOLE ERROR: EventSource cannot load http://127.0.0.1:8080/eventsource/resources/es-cors-basic.php. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://127.0.0.1:8000' is therefore not allowed access.
+[Worker] Test that basic EventSource cross-origin requests fail on redirect.
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+
+Starting worker: ../script-tests/eventsource-cors-redirect.js
+PASS [Worker] es = new EventSource("/resources/redirect.php?code=307&url=http://127.0.0.1:8080/eventsource/resources/es-cors-basic.php") did not throw exception.
+PASS [Worker] es.readyState is EventSource.CLOSED
+PASS successfullyParsed is true
+
+TEST COMPLETE
+