SPARK-3404 [BUILD] SparkSubmitSuite fails with "spark-submit exits with code 1"

This fixes the `SparkSubmitSuite` failure by setting `<spark.ui.port>0</spark.ui.port>` in the Maven build, to match the SBT build. This avoids a port conflict which causes failures.

(This also updates the `scalatest` plugin off of a release candidate, to the identical final release.)

Author: Sean Owen <sowen@cloudera.com>

Closes #2328 from srowen/SPARK-3404 and squashes the following commits:

512d782 [Sean Owen] Set spark.ui.port=0 in Maven scalatest config to match SBT build and avoid SparkSubmitSuite failure due to port conflict

pom.xml

@@ -888,7 +888,7 @@
         <plugin>
           <groupId>org.scalatest</groupId>
           <artifactId>scalatest-maven-plugin</artifactId>
-          <version>1.0-RC2</version>
+          <version>1.0</version>
           <configuration>
             <reportsDirectory>${project.build.directory}/surefire-reports</reportsDirectory>
             <junitxml>.</junitxml>
@@ -899,6 +899,7 @@
               <java.awt.headless>true</java.awt.headless>
               <spark.test.home>${session.executionRootDirectory}</spark.test.home>
               <spark.testing>1</spark.testing>
+              <spark.ui.port>0</spark.ui.port>
             </systemProperties>
           </configuration>
           <executions>