vtkTextSourceRepresentation was unnecessary doing a data-clone (despite the fact
that all data-server nodes have valid data). This added unnecessary
communication between all processes and hence was causing a performance
degradation as experienced by BUG #14221 (and other Catalyst users). Fixed that.
vtkTextSourceRepresentation still needs data delivered to client always (since
the 2D renderer is not composited), but we ensure that we no longer to any
gathers/scatters thus avoiding parallel communication.

Change-Id: I98a85ef4b911f813533ab7ed7c0ee4cee2adbca1