Update Spring test metadata

See https://github.com/TechEmpower/FrameworkBenchmarks/issues/2338

frameworks/Java/spring/benchmark_config.json

@@ -16,8 +16,8 @@
       "framework": "spring",
       "language": "Java",
       "orm": "Full",
-      "platform": "Servlet",
-      "webserver": "Tomcat",
+      "platform": "Undertow",
+      "webserver": "None",
       "os": "Linux",
       "database_os": "Linux",
       "display_name": "spring",