Check the size of the port vectors
Check the size of the port vectors

When setting the port type, the vectors get initialized on both maps, so
the size needs to be checked.

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