Changed all the pt-osc tests to use full_output, since output uses eval {}

t/pt-online-schema-change/skip_innodb.t

@@ -31,14 +31,11 @@ else {
 
 my $master_dsn = 'h=127.1,P=12348,u=msandbox,p=msandbox';
 my @args       = (qw(--lock-wait-timeout 3), '--max-load', ''); 
-my $output;
-my $retval;
 
-$output = output(
-   sub { $retval = pt_online_schema_change::main(@args,
+my ($output, $retval) = full_output(
+   sub { pt_online_schema_change::main(@args,
       "$master_dsn,D=mysql,t=user", "--alter", "add column (foo int)",
       qw(--dry-run)) },
-   stderr => 1,
 );
 
 like(