[opt] resolve conflict from test 4.1.x

Author: FlechazoW

impala/impala-sink/src/main/java/com/dtstack/flink/sql/sink/impala/ImpalaDialect.java

@@ -34,7 +34,6 @@
 import org.slf4j.LoggerFactory;
 
 import java.io.IOException;
-import java.rmi.RemoteException;
 import java.security.PrivilegedExceptionAction;
 import java.sql.Connection;
 import java.sql.DriverManager;
@@ -52,7 +51,6 @@
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.ScheduledThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
-import java.util.concurrent.atomic.AtomicReference;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;