Fix test failures due to incorrect use of chmod

Resolves #807.

Changes

@@ -20,6 +20,8 @@ Revision history for Perl extension App::Sqitch
      - Fixed invalid template resolution when adding a singe to multiple
        engines at once. Thanks to Christian Riedel for the detailed bug report
        (#795)!
+     - Fixed Oracle and Firebird test failures due to incorrect use of `chmod`.
+       Thanks to Slaven Rezić for the report and the fix (#807)!
 
 1.4.0 2023-08-01T23:37:30Z
      - Fixed Snowflake warehouse and role setup to properly quote identifiers

t/firebird.t

@@ -377,7 +377,7 @@ FSPEC: {
     my $iswin = App::Sqitch::ISWIN || $^O eq 'cygwin';
     my $fbsql = $tmp->file('fbsql' . ($iswin ? '.exe' : ''));
     $fbsql->touch;
-    chmod '0755', $fbsql unless $iswin;
+    chmod 0755, $fbsql unless $iswin;
 
     my $fs_mock = Test::MockModule->new('File::Spec');
     $fs_mock->mock(path => sub { $tmp });

t/oracle.t

@@ -156,7 +156,7 @@ ORACLE_HOME: {
     my $tmp = Path::Class::Dir->new("$tmpdir");
     my $sqlplus = $tmp->file($cli);
     $sqlplus->touch;
-    chmod '0755', $sqlplus unless $iswin;
+    chmod 0755, $sqlplus unless $iswin;
 
     local $ENV{ORACLE_HOME} = "$tmpdir";
     $target = App::Sqitch::Target->new(sqitch => $sqitch);
@@ -168,7 +168,7 @@ ORACLE_HOME: {
     $bin->mkpath;
     $sqlplus = $bin->file($cli);
     $sqlplus->touch;
-    chmod '0755', $sqlplus unless $iswin;
+    chmod 0755, $sqlplus unless $iswin;
 
     $target = App::Sqitch::Target->new(sqitch => $sqitch);
     isa_ok $ora = $CLASS->new(sqitch => $sqitch, target => $target), $CLASS;