[SPARK-8099] set executor cores into system in yarn-cluster mode

Author: Xutingjun <xutingjun@huawei.com>
Author: xutingjun <xutingjun@huawei.com>

Closes #6643 from XuTingjun/SPARK-8099 and squashes the following commits:

80b18cd [Xutingjun] change to STANDALONE | YARN
ce33148 [Xutingjun] set executor cores into system
e51cc9e [Xutingjun] set executor cores into system
0600861 [xutingjun] set executor cores into system

core/src/main/scala/org/apache/spark/deploy/SparkSubmit.scala

@@ -425,7 +425,6 @@ object SparkSubmit {
       // Yarn client only
       OptionAssigner(args.queue, YARN, CLIENT, sysProp = "spark.yarn.queue"),
       OptionAssigner(args.numExecutors, YARN, CLIENT, sysProp = "spark.executor.instances"),
-      OptionAssigner(args.executorCores, YARN, CLIENT, sysProp = "spark.executor.cores"),
       OptionAssigner(args.files, YARN, CLIENT, sysProp = "spark.yarn.dist.files"),
       OptionAssigner(args.archives, YARN, CLIENT, sysProp = "spark.yarn.dist.archives"),
       OptionAssigner(args.principal, YARN, CLIENT, sysProp = "spark.yarn.principal"),
@@ -446,7 +445,7 @@ object SparkSubmit {
       OptionAssigner(args.keytab, YARN, CLUSTER, clOption = "--keytab"),
 
       // Other options
-      OptionAssigner(args.executorCores, STANDALONE, ALL_DEPLOY_MODES,
+      OptionAssigner(args.executorCores, STANDALONE | YARN, ALL_DEPLOY_MODES,
         sysProp = "spark.executor.cores"),
       OptionAssigner(args.executorMemory, STANDALONE | MESOS | YARN, ALL_DEPLOY_MODES,
         sysProp = "spark.executor.memory"),