ajax.js passes context as jQuery object to attachBehaviors and detachBehaviors, should pass plain object

Problem

Since the introduction of active-link.js (#1979468: ".active" from linkGenerator(), l() and theme_links() forces an upper limit of per-page caching for all content containing links), whenever an ajax enabled form element executes commands, the following error occurs:

DrupalBehaviorError: attach ; l: context.querySelectorAll is not a function (active-link.js, row 48)

This is the interested line:

var activeLinks = context.querySelectorAll(selectors.join(','));

Here, the attach function rightly assumes that context is a plain object (as implied by the documentation of Drupal.attachBehaviors), so there is nothing wrong with it.
The error originates from ajax.js, where Drupal.attachBehaviors and Drupal.detachBehaviors are called passing the this.form variable as context, which is a jQuery object. The variable is created in the Drupal.ajax constructor:

  if (this.element.form) {
    this.form = $(this.element.form);
  }

Note that the bug has always been there, but attach functions almost always perform something like var $context = $(context), so it was never exposed.

Proposed resolution

Adjust all calls to Drupal.attachBehaviors and Drupal.detachBehaviors in ajax.js so that the plain dom object of the form is passed. Rename this.form throughout the script to this.$form so it's clear that the variable represents a jQuery object.