Script Loader: Partially revert [46550] as it brought in unrelated CSS changes.

[46550] was meant to revert [46440] but it also merged some unrelated CSS changes.

See #47069.

Built from https://develop.svn.wordpress.org/trunk@46559


git-svn-id: https://core.svn.wordpress.org/trunk@46356 1a063a9b-81f0-0310-95a4-ce76da25c4cd