tests - clean up - three commits (#1903)

* tests - cleanup rackup folder, add sleep.ru, add helpers/app.rb

* tests - change nextport to UniquePort.call, remove nextport, mutex

clean up, mutex removes port issues with parallel testing

* test_integration.rb - make UNIXSocket file names unique

test/test_integration.rb

@@ -9,12 +9,8 @@
 # TODO: remove stdout logging, get everything out of my rainbow dots
 
 class TestIntegration < Minitest::Test
-<<<<<<< HEAD
   HOST  = "127.0.0.1"
   TOKEN = "xxyyzz"
-=======
-  HOST = '127.0.0.1'
->>>>>>> Fixes Cluster worker shutdown/restart (#1908)
 
   def setup
     @state_path   = "test/test_#{name}_puma.state"