I just did the test, and I forgot to mention one issue I see now (if you look carefully it's in the example MANIFEST, but I didn't mention it)

javax.inject needs to be imported as well, since javax.inject.Qualifier is used on the new HibernateValidator annotation.

So that's basically one addition to cdi/pom.xml as follows:

<Import-Package>
    javax.validation.*;version="[2.0,3.0)",
    javax.annotation.*;version="[1.2,2.0)",
    javax.interceptor.*;version="[1.2,2.0)",
    javax.enterprise.*;version="[1.2,3.0)",
    javax.inject.*  
</Import-Package>

With that change applied I was able to run all Java EE 8 samples against Payara 5 alpha 1 updated with hibernate-validator.jar and hibernate-validator-cdi.jar 6.0.3 from the PR branch.