Add new DECIMAL testcase into t/rt122541-decimals.t

Add a new test case with CAST AS DECIMAL which verifies that support for
trailing zeros is working in Perl and which works also with new MySQL
server versions.

t/rt122541-decimals.t

@@ -11,10 +11,12 @@ require "lib.pl";
 
 my $dbh = DbiTestConnect($test_dsn, $test_user, $test_password, { PrintError => 0, RaiseError => 1 });
 
-plan tests => 2;
+plan tests => 4;
 
 for my $mariadb_server_prepare (0, 1) {
 	$dbh->{mariadb_server_prepare} = $mariadb_server_prepare;
+	is $dbh->selectrow_arrayref('SELECT CAST(DEGREES(0.00043) * 69 AS DECIMAL(65, 2))')->[0], '1.70',
+		'float casted to decimal with fixed length and trailing zeros returns correct value for mariadb_server_prepare=' . $mariadb_server_prepare;
 	SKIP: {
 	skip 'MySQL 8.0.22+ server have broken ROUND() function', 1 if $dbh->get_info($GetInfoType{SQL_DBMS_NAME}) eq 'MySQL' and $dbh->{mariadb_serverversion} >= 80022;
 	is $dbh->selectrow_arrayref('SELECT round(degrees(0.00043) * 69, 2)')->[0], '1.70',