parametrize internal tokenization

Change-Id: I19df6812cb39f5e48ae6aa5fd16951e18aef82a5
diff --git a/xt/benchmark.pl b/xt/benchmark.pl
index 9d0489a..4bdc255 100644
--- a/xt/benchmark.pl
+++ b/xt/benchmark.pl
@@ -77,7 +77,7 @@
   Dumbbench::Instance::PerlSub->new(
     name => 'SimpleConversion',
     code => sub {
-      `cat '$file' | perl '$script' > /dev/null 2>&1`
+      `cat '$file' | perl '$script' -ti > /dev/null 2>&1`
     }
   ),
   Dumbbench::Instance::PerlSub->new(