Shortcodes: Revert [46369] for now to allow more time to investigate and...

Shortcodes: Revert [46369] for now to allow more time to investigate and prepare for backward compatibility changes.

Also reverts follow-up changes in [46370] and [46465].

See #47863.
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git-svn-id: https://core.svn.wordpress.org/trunk@46351 1a063a9b-81f0-0310-95a4-ce76da25c4cd