Adapt to new hamcrest packaging

Hamcrest has changed its packaging in 2.x to a single jar. We currently depend on both the hamcrest-core and hamcrest-library instead of the new single jar shipped with hamcrest. Since modules still write JUnit 4 tests we should make sure to adhere to the advice at

http://hamcrest.org/JavaHamcrest/distributables#upgrading-from-hamcrest-1x

The docs are not totally correct as explained here https://github.com/hamcrest/JavaHamcrest/issues/224#issuecomment-449760045 since https://junit.org/junit4/dependencies.html JUnit 4 actually has a transitive dependency on hamcrest-core not hamcrest-library.