HDDS-9955. Simplify assertions in integration tests

[wzhallright]

What changes were proposed in this pull request?

Assertions in the form:

assertTrue(<x> == <y>)   
assertEquals(null, <x>) or assertTrue(<x> == null)
assertTrue(<x> != null)
assertEquals(<boolean>, <x>)

can be simplified to:

assertEquals(<x>, <y>)
assertNotNull(<x>)
assertTrue/assertFalse(<x>)
assertNull(<x>)

Not only are these simpler, some of them also provide more information in case of failure.

This PR updates such assertions in hadoop-ozone/integration-test.

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-9955

CI

https://github.com/wzhallright/ozone/actions/runs/7284783456

[adoroszlai]

Thanks @wzhallright for the patch.

[adoroszlai]

Note that TestOzoneFileInterfaces is being migrated to JUnit5 in #5838. The same changes are done in that PR, too. Please remove TestOzoneFileInterfaces from the patch to avoid conflicts.

[adoroszlai]

Let's also flip the arguments to match expected, actual order:

Suggested change

	assertEquals(leaderCount.size(), dnNum);
	assertEquals(dnNum, leaderCount.size());

[adoroszlai]

Suggested change

	assertEquals(leaderCount.get(entry.getKey()), leaderNumOfEachDn);
	assertEquals(leaderNumOfEachDn, leaderCount.get(entry.getKey()));

[adoroszlai]

Suggested change

	assertNotEquals(omKeyLocationInfo.getPartNumber(), -1));
	assertNotEquals(-1, omKeyLocationInfo.getPartNumber()));

[adoroszlai]

Suggested change

	assertEquals(locationInfoList.size(), 1);
	assertEquals(1, locationInfoList.size());

[wzhallright]

@adoroszlai Thank you for your detailed comments and suggestions, has fixed the comments, PTAL.