psql: Show notices immediately (again)

psql: Show notices immediately (again)

The new show-all-results feature in psql (7844c9918) went out of its
way to show notices next to the results of the statements (in a
multi-statement string) that caused them.  This also had the
consequence that notices for a single statement were not shown until
after the statement had executed, instead of right away.  After some
discussion, it seems very difficult to satisfy both of these goals, so
here we are giving up on the first goal and just show the notices as
we get them.  This restores the pre-7844c9918 behavior for notices.

Reported-by: Alastair McKinley <a.mckinley@analyticsengines.com>
Author: Fabien COELHO <coelho@cri.ensmp.fr>
Discussion: https://www.postgresql.org/message-id/flat/PAXPR02MB760039506C87A2083AD85575E3DA9%40PAXPR02MB7600.eurprd02.prod.outlook.com