Fix reactive sentinel circuit breaker tests (#3054) (#3063)

* Fix reactive sentinel circuit breaker tests

spring-cloud-alibaba-starters/spring-cloud-circuitbreaker-sentinel/src/test/java/com/alibaba/cloud/circuitbreaker/sentinel/ReactiveSentinelCircuitBreakerIntegrationTest.java

@@ -74,8 +74,9 @@ public void test() throws Exception {
 		// Then in the next 5s, the fallback method should be called.
 		for (int i = 0; i < 5; i++) {
 			StepVerifier.create(service.slow()).expectNext("fallback").verifyComplete();
-			Thread.sleep(1000);
+			Thread.sleep(900);
 		}
+		Thread.sleep(500);
 
 		// Half-open recovery (will re-open the circuit breaker).
 		StepVerifier.create(service.slow()).expectNext("slow").verifyComplete();
@@ -91,8 +92,9 @@ public void test() throws Exception {
 		for (int i = 0; i < 5; i++) {
 			StepVerifier.create(service.slowFlux()).expectNext("flux_fallback")
 					.verifyComplete();
-			Thread.sleep(1000);
+			Thread.sleep(900);
 		}
+		Thread.sleep(500);
 
 		// Half-open recovery (will re-open the circuit breaker).
 		StepVerifier.create(service.slowFlux()).expectNext("slowflux").verifyComplete();