HDDS-9524. Clean up wait for leader OM in integration tests

[david1859168]

What changes were proposed in this pull request?

MiniOzoneHAClusterImpl:

getOMLeader() returns current OM leader.
getOMLeader(boolean) optionally waits until OM leader is elected
There are some tests that implement the same "wait for leader OM" logic using the non-waiting getOMLeader().

hadoop-ozone/integration-test/src/test/java/org/apache/hadoop/ozone/om/TestAddRemoveOzoneManager.java
209:    GenericTestUtils.waitFor(() -> cluster.getOMLeader() != null, 500, 30000);
437:    GenericTestUtils.waitFor(() -> cluster.getOMLeader() != null, 500, 30000);

hadoop-ozone/integration-test/src/test/java/org/apache/hadoop/ozone/om/TestOzoneManagerHA.java
466:        getCluster().getOMLeader() != null, 500, timeout);

hadoop-ozone/integration-test/src/test/java/org/apache/hadoop/ozone/om/TestOzoneManagerHASnapshot.java
126:    await(120_000, 100, () -> cluster.getOMLeader() != null);
253:    await(180_000, 100, () -> cluster.getOMLeader() != null);

Goals of this task:
rename getOMLeader(boolean) to waitForLeaderOM() (the method is only called with true)
make waitForLeaderOM() public
replace duplicated wait logic in tests with a call to waitForLeaderOM()

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-9524

How was this patch tested?

Made changes and ran unit test.

[adoroszlai]

Thanks @david1859168 for the patch. Findbugs reports an unused variable:

M D DLS: Dead store to timeout in org.apache.hadoop.ozone.om.TestOzoneManagerHA.waitForLeaderToBeReady()  At TestOzoneManagerHA.java:[line 463]

https://github.com/david1859168/ozone/actions/runs/7652102229/job/20851218541#step:7:11

[adoroszlai]

Thanks @david1859168 for updating the patch, LGTM.

[aswinshakil]

Nice find. Thanks for the patch @david1859168 and Thanks for the review @adoroszlai

[adoroszlai]

Thanks @david1859168 for the patch, @aswinshakil for the review.