Fix assignment error in AbstractAsyncExecutionAspect

Issue: SPR-8772

org.springframework.aspects/src/main/java/org/springframework/scheduling/aspectj/AbstractAsyncExecutionAspect.aj

@@ -45,7 +45,7 @@ public abstract aspect AbstractAsyncExecutionAspect {
 			this.asyncExecutor = (AsyncTaskExecutor) executor;
 		}
 		else {
-			this.asyncExecutor = new TaskExecutorAdapter(asyncExecutor);
+			this.asyncExecutor = new TaskExecutorAdapter(executor);
 		}
 	}