Only skip low level lock test for RT #125977 on Moar

It works fine on JVM

S17-lowlevel/lock.t

@@ -88,7 +88,7 @@ plan 8;
       is @log.join(','), 'ale,porter,stout', 'Condition variable worked';
 }
 
-#?rakudo skip 'runs out of filehandles on OS X RT #125977'
+#?rakudo.moar skip 'runs out of filehandles on OS X RT #125977'
 {
     my $times = 100;
     my $tried;