Server shutdown warning when building native with Mandrel
Using Mandrel 20.1 with cleanup server option shows:

```
Status: Downloaded newer image for quay.io/quarkus/ubi-quarkus-mandrel:20.1.0.1.Alpha2-java11
quay.io/quarkus/ubi-quarkus-mandrel:20.1.0.1.Alpha2-java11
[INFO] [io.quarkus.deployment.pkg.steps.NativeImageBuildStep] Running Quarkus native-image plugin on GraalVM Version 20.1.0.1.Alpha2 56d4ee1b28 (Mandrel Distribution) (Java Version 11.0.8)
Warning: Ignoring server-mode native-image argument --server-shutdown.
Error: Please specify class containing the main entry point method. (see --help)
[INFO] [io.quarkus.deployment.pkg.steps.NativeImageBuildStep] docker run -v /root/quarkus/integration-tests/main/target/quarkus-integration-test-main-1.7.0.Final-native-image-source-jar:/project:z --env LANG=C --user 0:0 --rm quay.io/quarkus/ubi-quarkus-mandrel:20.1.0.1.Alpha2-java11 -J-Dsun.nio.ch.maxUpdateArraySize=100 -J-DCoordinatorEnvironmentBean.transactionStatusManagerEnable=false -J-Djava.util.logging.manager=org.jboss.logmanager.LogManager -J-Dcom.sun.xml.bind.v2.bytecode.ClassTailor.noOptimize=true -J-Drx.unsafe-disable=true -J-Dvertx.logger-delegate-factory-class-name=io.quarkus.vertx.core.runtime.VertxLogDelegateFactory -J-Dvertx.disableDnsResolver=true -J-Dio.netty.leakDetection.level=DISABLED -J-Dio.netty.allocator.maxOrder=1 -J-Duser.language=en -J-Dfile.encoding=UTF-8 -H:IncludeResources=test-resources/.*\\.txt --initialize-at-build-time= -H:InitialCollectionPolicy=com.oracle.svm.core.genscavenge.CollectionPolicy$BySpaceAndTime -H:+JNI -jar quarkus-integration-test-main-1.7.0.Final-runner.jar -H:FallbackThreshold=0 -H:+ReportExceptionStackTraces -H:+AddAllCharsets -H:EnableURLProtocols=http -H:-UseServiceLoaderFeature -H:+StackTrace quarkus-integration-test-main-1.7.0.Final-runner
[quarkus-integration-test-main-1.7.0.Final-runner:56]    classlist:  17,708.30 ms,  1.19 GB
```

Native image is built fine, but the warning above is related to server shutdown. Mandrel does not support server (`--no-server` already excludes the use of Mandrel), so we just need to extend server shutdown to non-Mandrel versions.

Related to https://github.com/graalvm/mandrel/issues/107.
diff --git a/core/deployment/src/main/java/io/quarkus/deployment/pkg/steps/NativeImageBuildStep.java b/core/deployment/src/main/java/io/quarkus/deployment/pkg/steps/NativeImageBuildStep.java
index 15c59625dc5..7e9e8fcf908 100644
--- a/core/deployment/src/main/java/io/quarkus/deployment/pkg/steps/NativeImageBuildStep.java
+++ b/core/deployment/src/main/java/io/quarkus/deployment/pkg/steps/NativeImageBuildStep.java
@@ -204,7 +204,7 @@ public NativeImageBuildItem build(NativeConfig nativeConfig, NativeImageSourceJa
 
         try {
             List<String> command = new ArrayList<>(nativeImage);
-            if (nativeConfig.cleanupServer) {
+            if (nativeConfig.cleanupServer && !graalVMVersion.isMandrel()) {
                 List<String> cleanup = new ArrayList<>(nativeImage);
                 cleanup.add("--server-shutdown");
                 final ProcessBuilder pb = new ProcessBuilder(cleanup.toArray(new String[0]));
['core/deployment/src/main/java/io/quarkus/deployment/pkg/steps/NativeImageBuildStep.java']