Encode the Last-Event-ID header in EventSource as UTF-8.

LayoutTests/http/tests/eventsource/resources/reconnect.php

Index: LayoutTests/http/tests/eventsource/resources/reconnect.php
diff --git a/LayoutTests/http/tests/eventsource/resources/reconnect.php b/LayoutTests/http/tests/eventsource/resources/reconnect.php
index 85a247de06aa8a8765aa9cc009c42e4186761f17..0639c9090535e144aed036e9e39f4cc5fa78437a 100644
--- a/LayoutTests/http/tests/eventsource/resources/reconnect.php
+++ b/LayoutTests/http/tests/eventsource/resources/reconnect.php
@@ -5,7 +5,8 @@ $lastEventId = $_SERVER['HTTP_LAST_EVENT_ID'];
 if ($lastEventId)
     echo "data: $lastEventId\n\n";
 else {
-    echo "id: 77\n";
+    # Include a non-ASCII character to test the client encodes it correctly.
+    echo "id: 77☃\n";
     echo "retry: 300\n";
     echo "data: hello\n\n";
     echo "data: discarded";