[JENKINS-18410] NPE from previous fix (fcdf749) under some conditions, which the test case was not exercising.
java.lang.NullPointerException
	at hudson.tasks.test.AggregatedTestResultPublisher$TestResultAction.getProject(AggregatedTestResultPublisher.java:173)
	at hudson.tasks.test.AggregatedTestResultPublisher$TestResultAction.<init>(AggregatedTestResultPublisher.java:146)
	at hudson.tasks.test.AggregatedTestResultPublisher$TestResultAction.<init>(AggregatedTestResultPublisher.java:135)
	at hudson.tasks.test.AggregatedTestResultPublisher.perform(AggregatedTestResultPublisher.java:90)