Fixes hazelcast#8900

Wrap ParseException with AssertionError to keep trying in case an
incorrectly formatted JSON string is received from the server. Also
close the HTTP client to prevent any possible resource leakage.

(cherry picked from commit a988ed8)

hazelcast/src/test/java/com/hazelcast/internal/management/ManagementCenterServiceIntegrationTest.java

@@ -18,6 +18,7 @@
 
 import com.eclipsesource.json.Json;
 import com.eclipsesource.json.JsonObject;
+import com.eclipsesource.json.ParseException;
 import com.hazelcast.config.Config;
 import com.hazelcast.core.Hazelcast;
 import com.hazelcast.monitor.TimedMemberState;
@@ -54,9 +55,12 @@ public class ManagementCenterServiceIntegrationTest extends HazelcastTestSupport
     private static final String clusterName = "Session Integration (AWS discovery)";
     private int portNum;
     private Server jettyServer;
+    private CloseableHttpClient client;
 
     @Before
     public void setUp() throws Exception {
+        client = HttpClientBuilder.create().disableRedirectHandling().build();
+
         portNum = availablePort();
         jettyServer = new Server(portNum);
         ServletHandler handler = new ServletHandler();
@@ -71,22 +75,27 @@ public void setUp() throws Exception {
     public void tearDown() throws Exception {
         Hazelcast.shutdownAll();
         jettyServer.stop();
+        client.close();
     }
 
     @Test
     public void testTimedMemberStateNotNull() {
         assertTrueEventually(new AssertTask() {
             @Override
             public void run() throws Exception {
-                CloseableHttpClient client = HttpClientBuilder.create().disableRedirectHandling().build();
                 HttpUriRequest request = new HttpGet("http://localhost:" + portNum + "/mancen/memberStateCheck");
                 HttpResponse response = client.execute(request);
                 HttpEntity entity = response.getEntity();
                 String responseString = EntityUtils.toString(entity);
                 assertNotNull(responseString);
                 assertNotEquals("", responseString);
 
-                JsonObject object = Json.parse(responseString).asObject();
+                JsonObject object;
+                try {
+                    object = Json.parse(responseString).asObject();
+                } catch (ParseException e) {
+                    throw new AssertionError("Failed to parse JSON: " + responseString);
+                }
                 TimedMemberState memberState = new TimedMemberState();
                 memberState.fromJson(object);
                 assertEquals(clusterName, memberState.getClusterName());
@@ -99,7 +108,6 @@ public void testGetTaskUrlEncodes() {
         assertTrueEventually(new AssertTask() {
             @Override
             public void run() throws Exception {
-                CloseableHttpClient client = HttpClientBuilder.create().disableRedirectHandling().build();
                 HttpUriRequest request = new HttpGet("http://localhost:" + portNum + "/mancen/getClusterName");
                 HttpResponse response = client.execute(request);
                 HttpEntity entity = response.getEntity();