OrderedPropertiesTest fails on Java 11 / OS X

When running on OS X 10.14 ( Mojave ) with openjdk 11, the OrderedPropertiesTest is failing. When using jdk1.8.0_192 instead, the test succeeds. 

Tests run: 1, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 0.05 sec <<< FAILURE! - in org.apache.nifi.minifi.bootstrap.util.OrderedPropertiesTest
testOrderedProperties(org.apache.nifi.minifi.bootstrap.util.OrderedPropertiesTest) Time elapsed: 0.05 sec <<< FAILURE!
org.junit.ComparisonFailure: expected:<[prop1=newVal1]> but was:<this is property 2>
at org.junit.Assert.assertEquals(Assert.java:115)
at org.junit.Assert.assertEquals(Assert.java:144)
at org.apache.nifi.minifi.bootstrap.util.OrderedPropertiesTest.testOrderedProperties(OrderedPropertiesTest.java:49)