[SPARK-33049][CORE] Decommission shuffle block test is flaky

[holdenk]

What changes were proposed in this pull request?

Increase the listener bus event length, syncrhonize the addition of blocks modified to the array list.

Why are the changes needed?

This test appears flaky in Jenkins (can not repro locally). Given that the index file made it through and the index file is only transferred after the data file, the only two reasons I could come up with an interminentent failure here are with the listenerbus dropping a message or the two block change messages being received at the same time.

Does this PR introduce any user-facing change?

No (test only).

How was this patch tested?

The tests still pass on my machine but they did before. We'll need to run it through jenkins a few times first.

[SparkQA]

Kubernetes integration test starting
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/33941/

[SparkQA]

Kubernetes integration test status success
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/33941/

[SparkQA]

Test build #129328 has finished for PR 29929 at commit 6518153.

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

[holdenk]

jenkins retest this please

[holdenk]

cc @dongjoon-hyun

[SparkQA]

Kubernetes integration test starting
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/33947/

[SparkQA]

Kubernetes integration test status success
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/33947/

[SparkQA]

Test build #129334 has finished for PR 29929 at commit 6518153.

• This patch fails due to an unknown error code, -9.
• This patch merges cleanly.
• This patch adds no public classes.

[holdenk]

Jenkins failure is unrelated.
Jenkins retest this please.

[dongjoon-hyun]

Retest this please.

[dongjoon-hyun]

Thank you, @holdenk . Merged to master for Apache Spark 3.1.0.

[SparkQA]

Test build #129386 has finished for PR 29929 at commit 6518153.

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