Fix PostgreSQL::Test aliasing for Perl v5.10.1.

This Perl segfaults if a declaration of the to-be-aliased package
precedes the aliasing itself.  Per buildfarm members lapwing and wrasse.
Like commit 20911775, back-patch to v10
(all supported versions).

Discussion: https://postgr.es/m/20220625171533.GA2012493@rfd.leadboat.com

src/test/perl/PostgreSQL/Test/Cluster.pm

@@ -5,14 +5,9 @@
 # package the same symbol table as the older package.  See PostgresNode::new
 # for supporting heuristics.
 
-package PostgreSQL::Test::Cluster;
-
 use strict;
 use warnings;
-
-use PostgresNode;
 BEGIN { *PostgreSQL::Test::Cluster:: = \*PostgresNode::; }
-
-use Exporter 'import';
+use PostgresNode ();
 
 1;

src/test/perl/PostgreSQL/Test/Utils.pm

@@ -3,14 +3,9 @@
 # Allow use of release 15+ Perl package name in older branches, by giving that
 # package the same symbol table as the older package.
 
-package PostgreSQL::Test::Utils;
-
 use strict;
 use warnings;
-
-use TestLib;
 BEGIN { *PostgreSQL::Test::Utils:: = \*TestLib::; }
-
-use Exporter 'import';
+use TestLib ();
 
 1;