Explicitly globalize some missing query globals in wp-settings.php

When WordPress is loaded in a function (e.g. unit tests) the variables initialized at the top level aren't globals, but we expect them to be.

Fixes #26867

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git-svn-id: https://core.svn.wordpress.org/trunk@26873 1a063a9b-81f0-0310-95a4-ce76da25c4cd