Revert Java 17 syntax to Java 8 in GemFireMockObjectsConfiguration.

Author: jxblum

spring-data-geode-test/src/main/java/org/springframework/data/gemfire/tests/mock/annotation/GemFireMockObjectsConfiguration.java

@@ -126,7 +126,10 @@ protected boolean isUseSingletonCacheConfigured() {
 
 					getRegion(bean)
 						.ifPresent(region -> {
-							if (bean instanceof Advised advisedBean) {
+							if (bean instanceof Advised) {
+
+								Advised advisedBean = (Advised) bean;
+
 								advisedBean.addAdvice(0, new CountMethodInterceptor(region));
 							}
 						});