This is a new web-first assertion that should be used like this:
```ts
test('should work', async ({ page }) => {
const locator = page.locator('body');
// New web-first assertion.
await expect(locator).toIntersectViewport();
// The same functionality.
await expect.poll(() => locator.viewportRatio()).toBeGreaterThan(0);
});
```
Fixes#8740
This patch changes `expect(locator).toHaveAttribute()` so that the
`value` argument can be omitted. When done so, the method will
assert attribute existance.
Fixes#16517
This moves some expect() matchers tests from test runner tests to page tests,
because these are implemented through a library call anyway.
Makes tests more readbable, faster and easier to test specific details.
