Tests: Disable a fragile link e2e test until it is improved

[gziolo]

Description

allows autocomplete suggestions to be selected with the mouse test from links spec fails very often on Travis. Let's disable it and try to improve until we enable it again.

When it fails, this is what is printed on the console:

FAIL test/e2e/specs/links.test.js (57.317s)
● Links › allows autocomplete suggestions to be selected with the mouse
expect(received).not.toBeNull()
Received: null
300 | // Expect that clicking on the autocomplete suggestion doesn't dismiss the link popover.
301 | await firstSuggestion.click();
> 302 | expect( await page.$( '.editor-url-popover' ) ).not.toBeNull();
| ^
303 |
304 | // Expect the url input value to have been updated with the post url.
305 | const inputValue = await page.evaluate( () => document.querySelector( '.editor-url-input input[aria-label="URL"]' ).value );
at Object.toBeNull (test/e2e/specs/links.test.js:302:55)
at tryCatch (node_modules/regenerator-runtime/runtime.js:62:40)
at Generator.invoke [as _invoke] (node_modules/regenerator-runtime/runtime.js:288:22)
at Generator.prototype.(anonymous function) [as next] (node_modules/regenerator-runtime/runtime.js:114:21)
at asyncGeneratorStep (test/e2e/specs/links.test.js:15:103)
at _next (test/e2e/specs/links.test.js:17:194)

By the way, we should double check it works as expected at the same time :)

Edit: In my tests, it didn't regress. It would be nice to discover why this test doesn't work as intended with Puppeteer.

[tofumatt]

I'm cool with skipping unreliable tests. It's not ideal, but I'd rather us trust the test suite and respect failures when they happen than spend time restarting Travis thrice before accepting the failure as legitimate 👍

[gziolo]

Yes, I had to restart Travis jobs like 10 times today because of this particular test.

[gziolo]

Opened a follow-up issue: #13044.