### 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>
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