Move comment-reply.js to the footer.

While it can function before the page is loaded, it works by moving the comment form, which is usually toward the bottom of the page. Please report any contraindications on the ticket.

props obenland.
fixes #12641.

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git-svn-id: http://core.svn.wordpress.org/trunk@27156 1a063a9b-81f0-0310-95a4-ce76da25c4cd