fix(service-worker): ignore passive mixed content requests (#25994)

Although [passive mixed content][1] requests (like images) only produce
a warning without a ServiceWorker, fetching it via a ServiceWorker
results in an error. See
https://github.com/angular/angular/issues/23012#issuecomment-376430187
for more details.

This commit makes the ServiceWorker ignore such requests and let them be
handled by the browser directly to avoid breaking apps that would work
without the ServiceWorker.

[1]: https://developers.google.com/web/fundamentals/security/prevent-mixed-content/what-is-mixed-content#passive_mixed_content

Fixes #23012

PR Close #25994

packages/service-worker/worker/testing/scope.ts

@@ -181,7 +181,7 @@ export class SwTestHarness implements ServiceWorkerGlobalScope, Adapter, Context
       return {origin: obj.origin, path: obj.pathname};
     } else {
       const obj = require('url').parse(url);
-      return {origin: obj.origin, path: obj.pathname};
+      return {origin: `${obj.protocol}//${obj.host}`, path: obj.pathname};
     }
   }