Fix JVMTI memory leak in FlightRecorder::flush (#325)

Fix JVMTI memory leak in FlightRecorder::flush

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Co-authored-by: jaroslav.bachorik <jaroslav.bachorik@datadoghq.com>

Author: jbachorik

ddprof-lib/src/main/cpp/flightRecorder.cpp

@@ -1534,18 +1534,19 @@ void FlightRecorder::flush() {
     jvmtiEnv* jvmti = VM::jvmti();
     JNIEnv* env = VM::jni();
 
-    jclass** classes = NULL;
+    jclass* classes = NULL;
     jint count = 0;
     // obtaining the class list will create local refs to all loaded classes,
     // effectively preventing them from being unloaded while flushing
-    jvmtiError err = jvmti->GetLoadedClasses(&count, classes);
+    jvmtiError err = jvmti->GetLoadedClasses(&count, &classes);
     rec->switchChunk(-1);
     if (!err) {
-      // deallocate all loaded classes
+      // delete all local references
       for (int i = 0; i < count; i++) {
         env->DeleteLocalRef((jobject) classes[i]);
-        jvmti->Deallocate((unsigned char*) classes[i]);
       }
+      // deallocate the class array
+      jvmti->Deallocate((unsigned char*) classes);
     }
   }
 }