WEBrick 1.4.2 differs from Ruby 2.6.6's WEBrick 1.4.2 about webrick HOT 8 CLOSED

$ g d test
diff --git test/webrick/test_httpproxy.rb test/webrick/test_httpproxy.rb
index a9f6f7d610..504eb1f915 100644
--- test/webrick/test_httpproxy.rb
+++ test/webrick/test_httpproxy.rb
@@ -213,7 +213,7 @@ def test_big_bodies
         end
       end
     end
-  end
+  end if RUBY_VERSION >= '2.5'

   def make_certificate(key, cn)
     subject = OpenSSL::X509::Name.parse("/DC=org/DC=ruby-lang/CN=#{cn}")
diff --git test/webrick/test_httpserver.rb test/webrick/test_httpserver.rb
index a6e70da7e8..2e5d44940c 100644
--- test/webrick/test_httpserver.rb
+++ test/webrick/test_httpserver.rb
@@ -253,7 +253,7 @@ def test_callbacks
       server.virtual_host(WEBrick::HTTPServer.new(vhost_config))

       Thread.pass while server.status != :Running
-      sleep 1 if RubyVM::MJIT.enabled? # server.status behaves unexpectedly with --jit-wait
+      sleep 1 if defined?(RubyVM::MJIT) && RubyVM::MJIT.enabled? # server.status behaves unexpectedly with --jit-wait
       assert_equal(1, started, log.call)
       assert_equal(0, stopped, log.call)
       assert_equal(0, accepted, log.call)
diff --git test/webrick/test_server.rb test/webrick/test_server.rb
index 5f7f3a0b58..8162a186db 100644
--- test/webrick/test_server.rb
+++ test/webrick/test_server.rb
@@ -65,7 +65,7 @@ def test_callbacks
     }
     TestWEBrick.start_server(Echo, config){|server, addr, port, log|
       true while server.status != :Running
-      sleep 1 if RubyVM::MJIT.enabled? # server.status behaves unexpectedly with --jit-wait
+      sleep 1 if defined?(RubyVM::MJIT) && RubyVM::MJIT.enabled? # server.status behaves unexpectedly with --jit-wait
       assert_equal(1, started, log.call)
       assert_equal(0, stopped, log.call)
       assert_equal(0, accepted, log.call)