Revert "[ruby/webrick] Fix shutdown_pipe test issue"

This reverts commit b8fdd38b2e.

test/webrick/test_server.rb

@@ -162,26 +162,15 @@ class TestWEBrickServer < Test::Unit::TestCase
   end
 
   def test_shutdown_pipe
-    loop_count = 0
-    server_threads = []
-    loop do
-      loop_count += 1
-      break if loop_count == 11
-
     pipe = IO.pipe
     server = WEBrick::GenericServer.new(
       :ShutdownPipe => pipe,
       :BindAddress => '0.0.0.0',
       :Port => 0,
       :Logger => WEBrick::Log.new([], WEBrick::BasicLog::WARN))
-      server_threads << Thread.start { server.start }
-      sleep 0.1 until server.status == :Running || !server_threads.last.status
-      if server_threads.last.status
+    server_thread = Thread.start { server.start }
     pipe.last.puts('')
-        break
-      end
-    end
-    assert_join_threads(server_threads)
+    assert_join_threads([server_thread])
   end
 
   def test_port_numbers