swift

3236bc26 - [region-isolation] Refactor out the stubify dead function if no longer used functionality from move only checker into its own pass and put it before region based isolation.

[region-isolation] Refactor out the stubify dead function if no longer used functionality from move only checker into its own pass and put it before region based isolation. I am doing this since region based isolation hit the same issue that the move checker did. So it makes sense to refactor the functionality into its own pass and move it into a helper pass that runs before both. It is very conservative and only stubifies functions that the specialization passes explicitly mark as this being ok to be done to.