Rename fetch layout tests.

LayoutTests/http/tests/fetch/window/cache-override.html

Index: LayoutTests/http/tests/fetch/window/cache-override.html
diff --git a/LayoutTests/http/tests/fetch/window/fetch.html b/LayoutTests/http/tests/fetch/window/cache-override.html
similarity index 93%
copy from LayoutTests/http/tests/fetch/window/fetch.html
copy to LayoutTests/http/tests/fetch/window/cache-override.html
index 44741f6d0807a2b78646dec379b4c54fd6d5ea98..5e13e7d86f7d2890c6bbb2891d9b24b05c8ef455 100644
--- a/LayoutTests/http/tests/fetch/window/fetch.html
+++ b/LayoutTests/http/tests/fetch/window/cache-override.html
@@ -12,7 +12,7 @@
 <script>
 function start(t) {
   var script = document.createElement('script');
-  script.src = '../script-tests/fetch.js?';
+  script.src = '../script-tests/cache-override.js?';
   script.addEventListener(
     'error',
     function() { unreached_rejection(t); });