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

This reverts commit b8fdd38.

test/webrick/test_server.rb

@@ -162,26 +162,15 @@ def <<(msg)
   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
-        pipe.last.puts('')
-        break
-      end
-    end
-    assert_join_threads(server_threads)
+    pipe = IO.pipe
+    server = WEBrick::GenericServer.new(
+      :ShutdownPipe => pipe,
+      :BindAddress => '0.0.0.0',
+      :Port => 0,
+      :Logger => WEBrick::Log.new([], WEBrick::BasicLog::WARN))
+    server_thread = Thread.start { server.start }
+    pipe.last.puts('')
+    assert_join_threads([server_thread])
   end
 
   def test_port_numbers