Fix NPE in integ tests

Author: zoewangg

.changes/next-release/feature-AWSCommonRuntimeClient-0306e36.json

@@ -1,5 +1,5 @@
 {
     "category": "AWS Common Runtime HTTP Client",
     "type": "feature", 
-    "description": "This release includes the preview release of the AWS Common Runtime HTTP client for the AWS SDK for Java v2. The code can be found in the `aws-crt-client` module. See our post over at the [AWS Developer Blog](https://aws.amazon.com/blogs/developer/category/developer-tools/aws-sdk-for-java/) for additional information."
+    "description": "This release includes the preview release of the AWS Common Runtime HTTP client for the AWS SDK for Java v2. The code can be found in the `aws-crt-client` module."
 }

http-clients/aws-crt-client/src/it/java/software/amazon/awssdk/http/crt/AwsCrtClientS3IntegrationTest.java

@@ -22,16 +22,14 @@
 import java.util.List;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
-import org.junit.After;
+import org.junit.AfterClass;
 import org.junit.Assert;
-import org.junit.Before;
+import org.junit.BeforeClass;
 import org.junit.Test;
 import software.amazon.awssdk.auth.credentials.AnonymousCredentialsProvider;
 import software.amazon.awssdk.core.ResponseBytes;
 import software.amazon.awssdk.core.async.AsyncResponseTransformer;
 import software.amazon.awssdk.crt.CrtResource;
-import software.amazon.awssdk.crt.io.EventLoopGroup;
-import software.amazon.awssdk.crt.io.HostResolver;
 import software.amazon.awssdk.http.async.SdkAsyncHttpClient;
 import software.amazon.awssdk.regions.Region;
 import software.amazon.awssdk.services.s3.S3AsyncClient;
@@ -52,14 +50,12 @@ public class AwsCrtClientS3IntegrationTest {
 
     private static Region REGION = Region.US_EAST_1;
 
-    private static EventLoopGroup eventLoopGroup;
-    private static HostResolver hostResolver;
     private static SdkAsyncHttpClient crtClient;
 
     private static S3AsyncClient s3;
 
-    @Before
-    public void setup() {
+    @BeforeClass
+    public static void setup() {
         CrtResource.waitForNoResources();
 
         crtClient = AwsCrtAsyncHttpClient.create();
@@ -71,12 +67,10 @@ public void setup() {
                 .build();
     }
 
-    @After
-    public void tearDown() {
+    @AfterClass
+    public static void tearDown() {
         s3.close();
         crtClient.close();
-        hostResolver.close();
-        eventLoopGroup.close();
         CrtResource.waitForNoResources();
     }