Only require libmanagement_ext if it's actually needed.

On some systems/apps, libawt_headless gets pulled in. This currently
brings in libmanagement_ext unconditionally. However, libmanagement_ext
should only be present for linking iff
com.sun.management.internal.OperatingSystemImpl class becomes reachable.

Closes: oracle#5119

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/jdk/JNIRegistrationManagementExt.java

@@ -43,15 +43,17 @@
 
 @AutomaticallyRegisteredFeature
 public class JNIRegistrationManagementExt extends JNIRegistrationUtil implements InternalFeature {
+
+    private static final String OPERATING_SYSTEM_IMPL = "com.sun.management.internal.OperatingSystemImpl";
     private NativeLibraries nativeLibraries;
 
     @Override
     public void beforeAnalysis(BeforeAnalysisAccess access) {
         nativeLibraries = ((BeforeAnalysisAccessImpl) access).getNativeLibraries();
 
-        rerunClassInit(access, "com.sun.management.internal.OperatingSystemImpl");
+        rerunClassInit(access, OPERATING_SYSTEM_IMPL);
 
-        access.registerReachabilityHandler(this::linkManagementExt, clazz(access, "com.sun.management.internal.OperatingSystemImpl"));
+        access.registerReachabilityHandler(this::linkManagementExt, clazz(access, OPERATING_SYSTEM_IMPL));
         PlatformNativeLibrarySupport.singleton().addBuiltinPkgNativePrefix("com_sun_management_internal_OperatingSystemImpl");
     }
 
@@ -77,7 +79,8 @@ private void linkManagementExt(@SuppressWarnings("unused") DuringAnalysisAccess
 
     @Override
     public void afterAnalysis(AfterAnalysisAccess access) {
-        if (NativeLibrarySupport.singleton().isPreregisteredBuiltinLibrary("awt_headless")) {
+        boolean managementExtNeeded = access.isReachable(clazz(access, OPERATING_SYSTEM_IMPL));
+        if (managementExtNeeded && NativeLibrarySupport.singleton().isPreregisteredBuiltinLibrary("awt_headless")) {
             /*
              * Ensure that `management_ext` comes before `awt_headless` on the linker command line.
              * This is necessary to prevent linker errors such as JDK-8264047.