Problem:
Container tests copy tested jdk into container to do testing on it. This however does not work correctly for builds, in which conf directory is symlinked (such as fedora/rhel packages), causing failures due to missing config files in container.

Solution:
Symlinks are followed when copying tested jdk.
This similar to JDK-8309138, but in jdk8u-dev repository, there is a separated DockerTestUtils.java in hotspot/test directory.