Upstream service worker tests to WPT

third_party/WebKit/LayoutTests/http/tests/serviceworker/resources/invalid-header-worker.js

-self.addEventListener('fetch', function(event) {
-    var url = event.request.url;
-    if (url.indexOf('dummy?test') == -1) {
-      return;
-    }
-    event.respondWith(new Promise(function(resolve) {
-        var headers = new Headers;
-        headers.append('foo', 'foo');
-        headers.append('foo', 'b\0r'); // header value with a null byte
-        resolve(new Response('hello world', {'headers': headers}));
-      }));
-  });