Add image loading spec related tests

LayoutTests/http/tests/resources/origin.php

Index: LayoutTests/http/tests/resources/origin.php
diff --git a/LayoutTests/http/tests/resources/origin.php b/LayoutTests/http/tests/resources/origin.php
new file mode 100644
index 0000000000000000000000000000000000000000..5a34e3add306dbde64ed6a3d30e86ee8087f6b9c
--- /dev/null
+++ b/LayoutTests/http/tests/resources/origin.php
@@ -0,0 +1,16 @@
+<?php
+
+$gotOrigin = 0;
+foreach (getallheaders() as $name => $value) {
+    if ($name == "Origin") {
+        $gotOrigin = 1;
+    }
+}
+
+if ($gotOrigin) {
+    header('Location: square100.png');
+}
+else {
+    header('Location: square200.png');
+}
+header('HTTP/1.1 302 Redirect');