I've seen builds failing in the wild during `junit` step execution with
an exception like
```
java.lang.NullPointerException: Cannot invoke "hudson.model.Run.getRootDir()" because "this.run" is null
at PluginClassLoader for junit//hudson.tasks.junit.TestResultAction.getDataFilePath(TestResultAction.java:154)
at PluginClassLoader for junit//hudson.tasks.junit.TestResultAction.loadCached(TestResultAction.java:317)
at PluginClassLoader for junit//hudson.tasks.junit.TestResultAction.load(TestResultAction.java:279)
at PluginClassLoader for junit//hudson.tasks.junit.TestResultAction.getResult(TestResultAction.java:166)
at PluginClassLoader for junit//hudson.tasks.junit.TestResultAction.getResult(TestResultAction.java:70)
at PluginClassLoader for junit//hudson.tasks.test.AbstractTestResultAction.findCorrespondingResult(AbstractTestResultAction.java:286)
at PluginClassLoader for junit//hudson.tasks.test.TestResult.getPreviousResult(TestResult.java:146)
at PluginClassLoader for junit//hudson.tasks.junit.TestResult.getPreviousResult(TestResult.java:467)
at PluginClassLoader for junit//hudson.tasks.junit.CaseResult.getPreviousResult(CaseResult.java:768)
at PluginClassLoader for junit//hudson.tasks.junit.CaseResult.recomputeFailedSinceIfNeeded(CaseResult.java:669)
at PluginClassLoader for junit//hudson.tasks.junit.CaseResult.freeze(CaseResult.java:950)
at PluginClassLoader for junit//hudson.tasks.junit.SuiteResult.freeze(SuiteResult.java:730)
at PluginClassLoader for junit//hudson.tasks.junit.TestResult.freeze(TestResult.java:1119)
at PluginClassLoader for junit//hudson.tasks.junit.TestResultAction.setResult(TestResultAction.java:125)
at PluginClassLoader for junit//hudson.tasks.junit.TestResultAction.<init>(TestResultAction.java:96)
at PluginClassLoader for junit//hudson.tasks.junit.JUnitResultArchiver.parseAndSummarize(JUnitResultArchiver.java:301)
at PluginClassLoader for junit//hudson.tasks.junit.pipeline.JUnitResultsStepExecution.run(JUnitResultsStepExecution.java:62)
at PluginClassLoader for junit//hudson.tasks.junit.pipeline.JUnitResultsStepExecution.run(JUnitResultsStepExecution.java:27)
at PluginClassLoader for workflow-step-api//org.jenkinsci.plugins.workflow.steps.SynchronousNonBlockingStepExecution.lambda$start$0(SynchronousNonBlockingStepExecution.java:47)
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
at java.base/java.lang.Thread.run(Thread.java:840)
```
While the root cause for such corruption is still to be identified, the
plugin should defend against that condition and ignore such a build.
Similar to jenkinsci/parallel-test-executor-plugin#282