Simplify test management
Simplify test management

Keeping track of implemented tests in a global map will allow adding a
new tests to only require adding a function and a CMake declaration.

mathstuf/sprokit,Kitware/sprokit,mathstuf/sprokit,linus-sherrill/sprokit,Kitware/sprokit,linus-sherrill/sprokit,Kitware/sprokit,mathstuf/sprokit,linus-sherrill/sprokit,mathstuf/sprokit,Kitware/sprokit,linus-sherrill/sprokit