chore: improve error message (#2222)

Author: yury-s

src/browserContext.ts

@@ -172,7 +172,7 @@ export abstract class BrowserContextBase extends ExtendedEventEmitter implements
     await pages[0].waitForLoadState();
     if (pages.length !== 1 || pages[0].url() !== 'about:blank') {
       await this.close().catch(e => null);
-      throw new Error('Arguments can not specify page to be opened');
+      throw new Error(`Arguments can not specify page to be opened (first url is ${pages[0].url()})`);
     }
   }
 }