programatic .click() of checkbox reports checkbox state inconsistenly to what is reported from a user click

[travi]

with a click handler attached to a checkbox, a user click and and programmatic .click() report opposite .is(':checked') results inside the click handler.

This causes QUnit tests to report failures with code that works when actual users interact with a page. It has also prevented me from using the same click handler for user clicks and programmatic .click()s in some instances.

I have run the attached QUnit test against 1.2.6, the lastest stable, and the nightly to verify this issue exists in all of those versions.

[travi]

QUnit test

[dmethvin]

Duplicate of #3827.