Fix flakiness in TestIcebergNessieCatalogConnectorSmokeTest

Due to concurrent commits, the default retry count (4) may not be
 sufficient for the commits to succeed.
The `TestIcebergNessieCatalogConnectorSmokeTest`, inheriting
concurrent execution mode from `AbstractTestQueryFramework`
is the root cause of the problem. This was addressed by overriding
 it to execute in a single thread.

plugin/trino-iceberg/src/test/java/io/trino/plugin/iceberg/catalog/nessie/TestIcebergNessieCatalogConnectorSmokeTest.java

@@ -27,6 +27,7 @@
 import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.TestInstance;
+import org.junit.jupiter.api.parallel.Execution;
 
 import java.io.IOException;
 import java.nio.file.Files;
@@ -42,8 +43,10 @@
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.junit.jupiter.api.Assumptions.abort;
 import static org.junit.jupiter.api.TestInstance.Lifecycle.PER_CLASS;
+import static org.junit.jupiter.api.parallel.ExecutionMode.SAME_THREAD;
 
 @TestInstance(PER_CLASS)
+@Execution(SAME_THREAD)
 public class TestIcebergNessieCatalogConnectorSmokeTest
         extends BaseIcebergConnectorSmokeTest
 {