[SPARK-25899][TESTS]Fix flaky CoarseGrainedSchedulerBackendSuite

[zsxwing]

What changes were proposed in this pull request?

I saw CoarseGrainedSchedulerBackendSuite failed in my PR and finally reproduced the following error on a very busy machine:

sbt.ForkMain$ForkError: org.scalatest.exceptions.TestFailedDueToTimeoutException: The code passed to eventually never returned normally. Attempted 400 times over 10.009828643999999 seconds. Last failure message: ArrayBuffer("2", "0", "3") had length 3 instead of expected length 4.

The logs in this test shows executor 1 was not up when the test failed.

18/10/30 11:34:03.563 dispatcher-event-loop-12 INFO CoarseGrainedSchedulerBackend$DriverEndpoint: Registered executor NettyRpcEndpointRef(spark-client://Executor) (172.17.0.2:43656) with ID 2
18/10/30 11:34:03.593 dispatcher-event-loop-3 INFO CoarseGrainedSchedulerBackend$DriverEndpoint: Registered executor NettyRpcEndpointRef(spark-client://Executor) (172.17.0.2:43658) with ID 3
18/10/30 11:34:03.629 dispatcher-event-loop-6 INFO CoarseGrainedSchedulerBackend$DriverEndpoint: Registered executor NettyRpcEndpointRef(spark-client://Executor) (172.17.0.2:43654) with ID 0
18/10/30 11:34:03.885 pool-1-thread-1-ScalaTest-running-CoarseGrainedSchedulerBackendSuite INFO CoarseGrainedSchedulerBackendSuite: 

===== FINISHED o.a.s.scheduler.CoarseGrainedSchedulerBackendSuite: 'compute max number of concurrent tasks can be launched' =====

And the following logs in executor 1 shows it was still doing the initialization when the timeout happened (at 18/10/30 11:34:03.885).

18/10/30 11:34:03.463 netty-rpc-connection-0 INFO TransportClientFactory: Successfully created connection to 54b6b6217301/172.17.0.2:33741 after 37 ms (0 ms spent in bootstraps)
18/10/30 11:34:03.959 main INFO DiskBlockManager: Created local directory at /home/jenkins/workspace/core/target/tmp/spark-383518bc-53bd-4d9c-885b-d881f03875bf/executor-61c406e4-178f-40a6-ac2c-7314ee6fb142/blockmgr-03fb84a1-eedc-4055-8743-682eb3ac5c67
18/10/30 11:34:03.993 main INFO MemoryStore: MemoryStore started with capacity 546.3 MB

Hence, I think our current 10 seconds is not enough on a slow Jenkins machine. This PR just increases the timeout from 10 seconds to 60 seconds to make the test more stable.

How was this patch tested?

Jenkins

[gatorsmile]

LGTM

[SparkQA]

Test build #98328 has finished for PR 22910 at commit 0a3095f.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[gatorsmile]

Thanks! Merged to master/2.4