[SPARK-13387][MESOS] Add support for SPARK_DAEMON_JAVA_OPTS with MesosClusterDispatcher.

## What changes were proposed in this pull request?

Add support for SPARK_DAEMON_JAVA_OPTS with MesosClusterDispatcher.

## How was the this patch tested?

Manual testing by launching dispatcher with SPARK_DAEMON_JAVA_OPTS

Author: Timothy Chen <tnachen@gmail.com>

Closes #11277 from tnachen/cluster_dispatcher_opts.

launcher/src/main/java/org/apache/spark/launcher/SparkClassCommandBuilder.java

@@ -48,8 +48,8 @@ class SparkClassCommandBuilder extends AbstractCommandBuilder {
     String memKey = null;
     String extraClassPath = null;
 
-    // Master, Worker, and HistoryServer use SPARK_DAEMON_JAVA_OPTS (and specific opts) +
-    // SPARK_DAEMON_MEMORY.
+    // Master, Worker, HistoryServer, ExternalShuffleService, MesosClusterDispatcher use
+    // SPARK_DAEMON_JAVA_OPTS (and specific opts) + SPARK_DAEMON_MEMORY.
     if (className.equals("org.apache.spark.deploy.master.Master")) {
       javaOptsKeys.add("SPARK_DAEMON_JAVA_OPTS");
       javaOptsKeys.add("SPARK_MASTER_OPTS");
@@ -69,6 +69,8 @@ class SparkClassCommandBuilder extends AbstractCommandBuilder {
     } else if (className.equals("org.apache.spark.executor.MesosExecutorBackend")) {
       javaOptsKeys.add("SPARK_EXECUTOR_OPTS");
       memKey = "SPARK_EXECUTOR_MEMORY";
+    } else if (className.equals("org.apache.spark.deploy.mesos.MesosClusterDispatcher")) {
+      javaOptsKeys.add("SPARK_DAEMON_JAVA_OPTS");
     } else if (className.equals("org.apache.spark.deploy.ExternalShuffleService") ||
         className.equals("org.apache.spark.deploy.mesos.MesosExternalShuffleService")) {
       javaOptsKeys.add("SPARK_DAEMON_JAVA_OPTS");