remove benchmark that tested code that has since been removed

benchmark/thread_alone.rb

@@ -1,20 +0,0 @@
-# encoding: UTF-8
-$LOAD_PATH.unshift File.expand_path(File.dirname(__FILE__) + '/../lib')
-
-require 'rubygems'
-require 'benchmark'
-require 'mysql2'
-
-iterations = 1000
-client = Mysql2::Client.new(:host => "localhost", :username => "root", :database => "test")
-query = lambda{ iterations.times{ client.query("SELECT mysql2_test.* FROM mysql2_test") } }
-Benchmark.bmbm do |x|
-  x.report('select') do
-    query.call
-  end
-  x.report('rb_thread_select') do
-    thread = Thread.new{ sleep(10) }
-    query.call
-    thread.kill
-  end
-end