In Eclipse Proton, there is a new "Contains test sources" attribute
on source folders. Test source folders and dependencies are shown
with a darker icon in the build path settings, the package explorer
and other locations.
See the Photon release notes [1] for details.
Add the necessary "test" attribute on the classpathentry.
This has no impact on earlier versions of Eclipse, or IDEs other
than Eclipse; they will simply ignore this attribute.
[1] https://www.eclipse.org/photon/noteworthy/
Change-Id: I9ff701bd2328cc9b6d7c4726ce51dc55345b3810
cc5c7f117d