chore: Fix ITMutableCredentialsTest in cloud-devel (#4383)

Author: sakthivelmanii

java-spanner/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITMutableCredentialsTest.java

@@ -22,6 +22,7 @@
 
 import com.google.auth.oauth2.GoogleCredentials;
 import com.google.auth.oauth2.ServiceAccountCredentials;
+import com.google.cloud.spanner.IntegrationTestEnv;
 import com.google.cloud.spanner.MutableCredentials;
 import com.google.cloud.spanner.SerialIntegrationTest;
 import com.google.cloud.spanner.Spanner;
@@ -32,6 +33,7 @@
 import java.io.InputStream;
 import java.nio.file.Files;
 import java.nio.file.Paths;
+import org.junit.ClassRule;
 import org.junit.Test;
 import org.junit.experimental.categories.Category;
 import org.junit.runner.RunWith;
@@ -44,6 +46,8 @@ public class ITMutableCredentialsTest {
   private static final String INVALID_CERT_PATH =
       "/com/google/cloud/spanner/connection/test-key.json";
 
+  @ClassRule public static final IntegrationTestEnv env = new IntegrationTestEnv();
+
   @Test
   public void testMutableCredentialsUpdateAuthorizationForRunningClient() throws IOException {
     GoogleCredentials validCredentials = null;
@@ -75,7 +79,7 @@ public void testMutableCredentialsUpdateAuthorizationForRunningClient() throws I
         new MutableCredentials((ServiceAccountCredentials) validCredentials);
 
     SpannerOptions options =
-        SpannerOptions.newBuilder()
+        env.getTestHelper().getOptions().toBuilder()
             // this setting is required in the scenario SPANNER_EMULATOR_HOST is set otherwise
             // SpannerOptions overrides credentials to NoCredentials
             .setEmulatorHost(null)