Add an assertion to AopUtils.KotlinDelegate#invokeSuspendingFunction

See spring-projectsgh-22462

Author: sdeleuze

spring-aop/src/main/java/org/springframework/aop/support/AopUtils.java

@@ -372,6 +372,7 @@ private static class KotlinDelegate {
 
 		public static Publisher<?> invokeSuspendingFunction(Method method, Object target, Object... args) {
 			Continuation<?> continuation = (Continuation<?>) args[args.length -1];
+			Assert.state(continuation != null, "No Continuation available");
 			CoroutineContext context = continuation.getContext().minusKey(Job.Key);
 			return CoroutinesUtils.invokeSuspendingFunction(context, method, target, args);
 		}