pgsql: For PostgreSQL::Test compatibility, alias entire package symbol

For PostgreSQL::Test compatibility, alias entire package symbol tables.

Remove the need to edit back-branch-specific code sites when
back-patching the addition of a PostgreSQL::Test::Utils symbol.  Replace
per-symbol, incomplete alias lists.  Give old and new package names the
same EXPORT and EXPORT_OK semantics.  Back-patch to v10 (all supported
versions).

Reviewed by Andrew Dunstan.

Discussion: https://postgr.es/m/20220622072144.GD4167527@rfd.leadboat.com

Branch
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REL_10_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/38790408b02083e00d0f01c28ac6a25d82c328cc

Modified Files
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src/test/perl/PostgreSQL/Test/Cluster.pm |  9 +++++---
src/test/perl/PostgreSQL/Test/Utils.pm   | 33 ++++--------------------------
src/test/perl/PostgresNode.pm            | 21 ++++++++++---------
src/test/perl/TestLib.pm                 | 35 --------------------------------
4 files changed, 21 insertions(+), 77 deletions(-)