swift234

Add a caller to _Prespecialize._specializeArrays() and _Prespecialize._specializeRanges() to keep them alive

We now run a dead function elim before running any generic specializer. generic specializer generates some
prespecialized functions and explicitly keep them alive (i.e. make them not removeable by dead function elim)

However, the recently added dead function elimination gets rid of the calls which the prespecialization uses
to generate the prespecialization.

Create a caller with special name (avoid conflict) to make sure the specialization does happen.

Hopefully, eventually we will be able to move to a cleaner approach to do prespecialization.

rdar://24543234