Review fixes for spring-webflux-5.0:testing (open-telemetry#17748)

Author: otelbot[bot]

instrumentation/spring/spring-webflux/spring-webflux-5.0/testing/src/main/java/io/opentelemetry/instrumentation/spring/webflux/server/AbstractSpringWebFluxServerTest.java

@@ -31,7 +31,7 @@ public abstract class AbstractSpringWebFluxServerTest
   static final InstrumentationExtension testing = HttpServerInstrumentationExtension.forAgent();
 
   @Override
-  public ConfigurableApplicationContext setupServer() {
+  protected ConfigurableApplicationContext setupServer() {
     SpringApplication app = new SpringApplication(getApplicationClass());
     Map<String, Object> properties = new HashMap<>();
     properties.put("server.port", port);
@@ -43,7 +43,7 @@ public ConfigurableApplicationContext setupServer() {
   }
 
   @Override
-  public void stopServer(ConfigurableApplicationContext configurableApplicationContext) {
+  protected void stopServer(ConfigurableApplicationContext configurableApplicationContext) {
     configurableApplicationContext.close();
   }