add small utility for benchmarking.

* benchmark/lib/load.rb: add small utility which requires
  benchmark-driver.rb. You can load this file and can
  use benchmark-driver.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64870 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

benchmark/lib/load.rb

@@ -0,0 +1,2 @@
+$:.unshift(File.join(__dir__, '../benchmark-driver/lib'))
+require 'benchmark_driver'