pgsql: psql: Add tests for \errverbose

psql: Add tests for \errverbose

This is another piece of functionality that happens while a user query
is being sent and which did not have any test coverage.

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/d3ab618290543017402b3bec9d36dde881becb18

Modified Files
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src/bin/psql/t/001_basic.pl | 47 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 47 insertions(+)