Handle multiple delegated selectors on tooltip and popover nodes

Fixes #14167.  This change just stores an hash of multiple tooltip or popover objects on the node when a selector is provided.  I wasn't sure whether to use an array or a hash, but I went with a hash indexed by the selector so that I could preserve the behavior that you cannot reinitialize a node with the same selector.
Check if the second popover is also removed from the DOM on a subsequent click on the trigger. Also, please add "second" or "first" to the messages to be able to clearly identify the popover, just like you did in the tooltip test case.