[SPARK-29112][YARN] Expose more details when ApplicationMaster reporter faces a fatal exception

### What changes were proposed in this pull request?
In `ApplicationMaster.Reporter` thread, fatal exception information is swallowed. It's better to expose it.
We found our thrift server was shutdown due to a fatal exception but no useful information from log.

> 19/09/16 06:59:54,498 INFO [Reporter] yarn.ApplicationMaster:54 : Final app status: FAILED, exitCode: 12, (reason: Exception was thrown 1 time(s) from Reporter thread.)
19/09/16 06:59:54,500 ERROR [Driver] thriftserver.HiveThriftServer2:91 : Error starting HiveThriftServer2
java.lang.InterruptedException: sleep interrupted
        at java.lang.Thread.sleep(Native Method)
        at org.apache.spark.sql.hive.thriftserver.HiveThriftServer2$.main(HiveThriftServer2.scala:160)
        at org.apache.spark.sql.hive.thriftserver.HiveThriftServer2.main(HiveThriftServer2.scala)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.apache.spark.deploy.yarn.ApplicationMaster$$anon$4.run(ApplicationMaster.scala:708)

### Does this PR introduce any user-facing change?
No

### How was this patch tested?
Manual test

Closes #25810 from LantaoJin/SPARK-29112.

Authored-by: LantaoJin <jinlantao@gmail.com>
Signed-off-by: jerryshao <jerryshao@tencent.com>

Author: LantaoJin

resource-managers/yarn/src/main/scala/org/apache/spark/deploy/yarn/ApplicationMaster.scala

@@ -578,7 +578,11 @@ private[spark] class ApplicationMaster(
             e.getMessage)
         case e: Throwable =>
           failureCount += 1
-          if (!NonFatal(e) || failureCount >= reporterMaxFailures) {
+          if (!NonFatal(e)) {
+            finish(FinalApplicationStatus.FAILED,
+              ApplicationMaster.EXIT_REPORTER_FAILURE,
+              "Fatal exception: " + StringUtils.stringifyException(e))
+          } else if (failureCount >= reporterMaxFailures) {
             finish(FinalApplicationStatus.FAILED,
               ApplicationMaster.EXIT_REPORTER_FAILURE, "Exception was thrown " +
                 s"$failureCount time(s) from Reporter thread.")