It has been unintendedly possible to both view and edit users from a different site than the current site in multisite environments. Moreover, when passing roles to a user in an update request, that user would implicitly be added to the current site.
This changeset removes the incorrect behavior for now in order to be able to provide a proper REST API workflow for managing multisite users in the near future. Related unit tests have been adjusted as well.
Props jnylen0, jeremyfelt, johnjamesjacoby.
Merges [40106] to the 4.7 branch.
Fixes#39701.
git-svn-id: https://develop.svn.wordpress.org/branches/4.7@40111 602fd350-edb4-49c9-b593-d223f7449a82
caebbb456e