Fix performance issue with CellSetSingleType reverse connections

When building the reverse connections (visit points with cells) for
`CellSetSingleType`, the fast path for building these was not built due
to a templating error.
5 jobs for single-type-reverse-connection
Status Name Job ID Coverage
  External
passed cdash-buildbot

running vtk-m-dragnipur-osx-shared-debug+32bit_ids+64bit_coords+clang+tbb

1432:01:47

running vtk-m-dragnipur-osx-static-release+64bit_coords+clang+tbb

1432:01:47

running vtk-m-osheim-windows-shared-debug+ninja-vs-2017+tbb

1432:01:46

running vtk-m-osheim-windows-static-release+ninja-vs-2017+tbb

1432:01:47