Add QUnit to WordPress core for JavaScript unit testing.

props jorbin.
see #25088.


git-svn-id: https://develop.svn.wordpress.org/trunk@25166 602fd350-edb4-49c9-b593-d223f7449a82
Add QUnit tests for password-strength-meter.js.

props jorbin.
see #25088.


git-svn-id: https://develop.svn.wordpress.org/trunk@25167 602fd350-edb4-49c9-b593-d223f7449a82
Improve the include / exclude SQL generation in `get_pages()` by using `IN` and `NOT IN` where applicable. Adds unit tests for include / exclude.

Fixes #22074.



git-svn-id: https://develop.svn.wordpress.org/trunk@25168 602fd350-edb4-49c9-b593-d223f7449a82