Use a single executor service for DriverService and DriverCommandExecutor

Author: pujagani

java/client/src/org/openqa/selenium/remote/service/DriverCommandExecutor.java

@@ -47,7 +47,7 @@
 public class DriverCommandExecutor extends HttpCommandExecutor implements Closeable {
 
   private final DriverService service;
-  private final ExecutorService executorService = Executors.newFixedThreadPool(2,  r -> {
+  private static final ExecutorService executorService = Executors.newFixedThreadPool(2,  r -> {
     Thread thread = new Thread(r);
     thread.setName("Driver Command Executor");
     thread.setDaemon(true);

java/client/src/org/openqa/selenium/remote/service/DriverService.java

@@ -60,7 +60,7 @@
  */
 public class DriverService implements Closeable {
   protected static final Duration DEFAULT_TIMEOUT = Duration.ofSeconds(20);
-  private final ExecutorService executorService = Executors.newFixedThreadPool(2, r -> {
+  private static final ExecutorService executorService = Executors.newFixedThreadPool(2, r -> {
     Thread thread = new Thread(r);
     thread.setName("Driver Service Executor");
     thread.setDaemon(true);