Fix NPD when using goto on a second page

[ankur22]

What?

This fixes an issue when working with a second tab (i.e. opening a new page in the same existing browserContext), and navigating to a url.

You can also test with the following test script to see what happens without the fix and with the fix:

import { browser } from "k6/x/browser";

export const options = {
  scenarios: {
    ui: {
      executor: "shared-iterations",
      options: {
        browser: {
          type: "chromium",
        },
      },
    },
  }
};

export default async function () {
  const page = browser.newPage();
  await page.goto("https://k6.io", { waitUntil: "networkidle" });

  const context = browser.context();
  const page2 = context.newPage();
  await page2.goto("https://k6.io", { waitUntil: "networkidle" });

  page.close();
}

Why?

This issue would arise as soon as any API is used from the new page instance. This was occurring due to the unmapped browserContext when getting it from the browser.

Checklist

• I have performed a self-review of my code
• I have added tests for my changes
• I have commented on my code, particularly in hard-to-understand areas

Related PR(s)/Issue(s)