[JENKINS-75532] Fix compatibility layer

[basil]

Amends #383.

Testing done

CI build. Also, with

diff --git a/plugin/src/test/java/org/jenkinsci/plugins/workflow/WorkflowTest.java b/plugin/src/test/java/org/jenkinsci/plugins/workflow/WorkflowTest.java
index 76181b3e..cf360839 100644
--- a/plugin/src/test/java/org/jenkinsci/plugins/workflow/WorkflowTest.java
+++ b/plugin/src/test/java/org/jenkinsci/plugins/workflow/WorkflowTest.java
@@ -205,7 +205,7 @@ public class WorkflowTest {
             @Override public void onResume() {
                 super.onResume();
                 try {
-                    listener.getLogger().println("again running as " + flow.getAuthentication2().getName() + " from " + Thread.currentThread().getName());
+                    listener.getLogger().println("again running as " + flow.getAuthentication().getName() + " from " + Thread.currentThread().getName());
                 } catch (Exception x) {
                     getContext().onFailure(x);
                 }

I was able to reproduce the problem running WorkflowTest#authentication. After this PR, could no longer reproduce.

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