Pad constant if needed when broadcasted to more cells than available

The issue with changes to the number of memory cells not being propagated from manager to correction devices turned out be exceptions thrown in preReconfigure on the correction device side. These were mostly related to trying to broadcast a constant of smaller size to more cells, e.g. 202 cells to 352 cells. This MR hotfixes this by padding said constants with 0/1.

Also contained is a small fix for SlopesPC where some intermediate result is allocated to target shape, not constant shape, raising an exception in any mismatch scenario.

@ahmedk @danilevc