Added SemaphoreStep.waitForStart() for workflow to wait until semapho…

[cdgopal]

Description and fix:
Previously, reliance on specific console messages for synchronization could lead to inconsistency and intermittent failures. By shifting to semaphore-based synchronization, the workflow ensures stability and predictability in execution.

Transitioning to SemaphoreStep.waitForStart() provides a more reliable synchronization approach, reducing flakiness risk linked to console message dependency.

Following is the error:

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[jglick]

compare

support-core-plugin/src/test/java/com/cloudbees/jenkins/support/impl/NodeExecutorsTest.java

Line 172 in a457dfc

p.setDefinition(new CpsFlowDefinition("node('test') {semaphore 'wait'}", true));

and

support-core-plugin/src/test/java/com/cloudbees/jenkins/support/impl/NodeExecutorsTest.java

Line 197 in a457dfc

SemaphoreStep.success("wait/1", null);