Cleanup perl code from unused variables and routines

This commit removes unused variables and routines from some perl code
that have accumulated across the years.  This touches the following
areas:
- Wait event generation script.
- AdjustUpgrade.pm.
- TAP perl code

Author: Alexander Lakhin
Reviewed-by: Dagfinn Ilmari Mannsåker
Discussion: https://postgr.es/m/70b340bc-244a-589d-ef8b-d8aebb707a84@gmail.com

contrib/amcheck/t/001_verify_heapam.pl

@@ -9,7 +9,7 @@ use PostgreSQL::Test::Utils;
 
 use Test::More;
 
-my ($node, $result);
+my $node;
 
 #
 # Test set-up
@@ -87,19 +87,6 @@ sub relation_filepath
 	return "$pgdata/$rel";
 }
 
-# Returns the fully qualified name of the toast table for the named relation
-sub get_toast_for
-{
-	my ($relname) = @_;
-
-	return $node->safe_psql(
-		'postgres', qq(
-		SELECT 'pg_toast.' || t.relname
-			FROM pg_catalog.pg_class c, pg_catalog.pg_class t
-			WHERE c.relname = '$relname'
-			  AND c.reltoastrelid = t.oid));
-}
-
 # (Re)create and populate a test table of the given name.
 sub fresh_test_table
 {

contrib/amcheck/t/002_cic.pl

@@ -10,7 +10,7 @@ use PostgreSQL::Test::Utils;
 
 use Test::More;
 
-my ($node, $result);
+my $node;
 
 #
 # Test set-up