HDDS-10557. TestBlockOutputStream#testWriteExactlyFlushSize is flaky

[chungen0126]

What changes were proposed in this pull request?

Fix test failure:

Error:  org.apache.hadoop.ozone.client.rpc.TestBlockOutputStream.testWriteExactlyFlushSize(boolean)[2]  Time elapsed: 0.06 s  <<< FAILURE!
org.opentest4j.AssertionFailedError: expected: <2> but was: <1>
	at org.junit.jupiter.api.AssertionFailureBuilder.build(AssertionFailureBuilder.java:151)
	at org.junit.jupiter.api.AssertionFailureBuilder.buildAndThrow(AssertionFailureBuilder.java:132)
	at org.junit.jupiter.api.AssertEquals.failNotEqual(AssertEquals.java:197)
	at org.junit.jupiter.api.AssertEquals.assertEquals(AssertEquals.java:166)
	at org.junit.jupiter.api.AssertEquals.assertEquals(AssertEquals.java:161)
	at org.junit.jupiter.api.Assertions.assertEquals(Assertions.java:632)
	at org.apache.hadoop.ozone.client.rpc.TestBlockOutputStream.testWriteExactlyFlushSize(TestBlockOutputStream.java:279)

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-10557

How was this patch tested?

Before fixed: https://github.com/chungen0126/ozone/actions/runs/8740583632

Tested successful 10*30 times after fixed: https://github.com/chungen0126/ozone/actions/runs/8780103858

[adoroszlai]

I don't see how this is specific to hsync.

[adoroszlai]

@chungen0126 can you share link to repeated run with the current state of the fix?

[chungen0126]

@chungen0126 can you share link to repeated run with the current state of the fix?

Passed 10x30 interations: https://github.com/chungen0126/ozone/actions/runs/9017804749

[adoroszlai]

Thanks @chungen0126 for the fix, @smengcl for the review.