app_pentominio.yml: drop unnecessary prelude

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63913 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
2018-07-09 12:50:50 +00:00 · 2018-07-09 12:50:50 +00:00 · 14153a9bab
--- a/benchmark/app_pentomino.yml
+++ b/benchmark/app_pentomino.yml
@ -1,4 +1,3 @@
-prelude: |
 benchmark:
  app_pentomino: |
    # This program is contributed by Shin Nishiyama