CXX-2048 Temporarily skip tests on PPC Ubuntu 16.04
CXX-2048 Temporarily skip tests on PPC Ubuntu 16.04

Ubuntu 16.04 PPC was EOL'd by MongoDB in 4.0.

But cannot upgrade hosts to PPC Ubuntu 18.04 until hosts can run cmake.

The "latest" unreleased download includes a copy of mongocryptd that
does not have the latest changes necessary.

mongodb/mongo-cxx-driver,mongodb/mongo-cxx-driver,mongodb/mongo-cxx-driver,mongodb/mongo-cxx-driver