The junit:junit Maven artifact includes a bundled version of hamcrest
core. For projects that depend on later versions of hamcrest this causes
significant issues in terms of dependency management.

The spring-test module now depends on junit:junit-dep, thus allowing
developers to better manage their test dependencies on a more fine
grained level.

Also tidied up dependency issues regarding hamcrest-core and
hamcrest-all across the build.

Issue: SPR-6966