add large stdout fixture program

fixtures/large_stdout/Procfile

@@ -0,0 +1,2 @@
+stdout1: ruby ./stdout.rb
+stdout2: ruby ./stdout.rb

fixtures/large_stdout/stdout.rb

@@ -0,0 +1,10 @@
+#!/usr/bin/env ruby
+
+$stdout.sync = true
+
+10.times do |i|
+  puts "sample log message... " * rand(i*1000) + "ok - #{i}"
+  sleep 1
+end
+
+puts "finish!"