[SPARK-3560] Fixed setting spark.jars system property in yarn-cluster mode

Author: Victsm <victor.nju@gmail.com>
Author: Min Shen <mshen@linkedin.com>

Closes #2449 from Victsm/SPARK-3560 and squashes the following commits:

918405a [Victsm] Removed the additional space
4502a2a [Min Shen] [SPARK-3560] Fixed setting spark.jars system property in yarn-cluster mode.
[Minor Hot Fix] Move a line in SparkSubmit to the right place

This was introduced in #2449

Author: Andrew Or <andrewor14@gmail.com>

Closes #2452 from andrewor14/standalone-hot-fix and squashes the following commits:

d5190ca [Andrew Or] Put that line in the right place

(cherry picked from commit 9306297d1d888d0430f79b2133ee7377871a3a18)
Signed-off-by: Andrew Or <andrewor14@gmail.com>