Accessibility: Script Loader: Add jQuery as dependency of `admin-bar`.

On the front end, themes that don't use jQuery make the admin bar fallback to the non-jQuery implementation. Some important features miss from the non-jQuery `admin-bar.js` part, for example `hoverintent` and, most importantly, the touch events for the mobile menu don't work at all.

Enqueueing jQuery is the simplest option for now. For the future, a complete rewriting of `admin-bar.js` in plain JavaScript is highly recommended.

See #47069.

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git-svn-id: https://core.svn.wordpress.org/trunk@46238 1a063a9b-81f0-0310-95a4-ce76da25c4cd