Revert [23467]. Removes structured-post-format theme support.

see #23347, #24452. closes #24453.

git-svn-id: https://core.svn.wordpress.org/trunk@24386 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Revert [23450]. Removes post format compat.

see #23347, #24452. closes #24454.

git-svn-id: https://core.svn.wordpress.org/trunk@24387 1a063a9b-81f0-0310-95a4-ce76da25c4cd