Make AspectJ pointcut in test more robust

The previous pointcut attempted to match against a local lambda type;
however, that pointcut was unreliable and failed sporadically.

This commit therefore changes the pointcut so that it specifically
targets the get() method of a subtype of Supplier, which seems to result
in reliable pointcut matching.

spring-context/src/test/java/org/springframework/aop/aspectj/autoproxy/AspectJAutoProxyCreatorTests.java

@@ -609,7 +609,7 @@ abstract class AbstractProxyTargetClassConfig {
 	@Aspect
 	static class SupplierAdvice {
 
-		@Around("execution(public * org.springframework.aop.aspectj.autoproxy..*.*(..))")
+		@Around("execution(* java.util.function.Supplier+.get())")
 		Object aroundSupplier(ProceedingJoinPoint joinPoint) throws Throwable {
 			return "advised: " + joinPoint.proceed();
 		}