Some of the serialization tests need to be updated to run in headless mode.
This is covered by 7162111. Until this happens, they will fail intermittently
on MacOS. JDK8 has the following entries in jdk/test/ProblemList.txt:
# 7162111 - these tests need to be updated to run headless
These entries should be added to jdk7u/jdk as well.