Skip full pageload wait on non-jQuery pages in waitForAjaxLoad

[lbajsarowicz]

Description

MagentoWebDriver::waitForAjaxLoad() waits for jQuery to be idle:

$this->waitForJS('return !!window.jQuery && window.jQuery.active == 0;', $timeout);

On a page that does not load jQuery, !!window.jQuery is always false, so the
expression is never truthy. waitForJS() therefore polls until it times out and
throws, and the catch block then sleeps another full pageload_timeout:

} catch (\Exception $exceptione) {
    $this->debug("js never executed, performing {$timeout} second wait.");
    $this->wait($timeout);
}

Net effect: roughly 2× WAIT_TIMEOUT (60s with the default 30s timeout) is burned on
every waitForAjaxLoad() call on any non-jQuery page — and waitForPageLoad() calls
waitForAjaxLoad() on every navigation. This penalizes storefront/headless flows and any
theme that does not ship jQuery.

Fixed Issues

Part of #925

Fix

Treat an absent jQuery as "no AJAX pending" so the condition resolves immediately instead
of timing out:

$this->waitForJS('return (typeof window.jQuery === "undefined") || window.jQuery.active == 0;', $timeout);

• On pages with jQuery (all Magento Admin pages): behavior is unchanged — the
  window.jQuery.active == 0 branch is evaluated exactly as before.
• On pages without jQuery: the check returns immediately, eliminating the double
  full-timeout wait.

The trailing $this->wait(1) settle buffer is intentionally left in place.

Manual testing scenarios

1. Run any test that navigates to a storefront page not using jQuery and observe that the
   step no longer stalls for ~2 × WAIT_TIMEOUT.
2. Run existing Admin tests (jQuery present) and confirm timing/behavior is unchanged.

Questions or comments

Isolated one-line change. Follow-ups from #925 (per-step getLog/getCurrentURL chatter,
loading-mask polling, session reuse) will come as separate PRs with timing evidence.

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All automated tests passed successfully (unit suite green locally; develop)