Integration test needed for the ACForce estimator

QMCPACK runs with the ACForce estimator crash at launch with the latest code (since around Jan 16). The error message is something like the following:

> Resetting Properties of the walkers 1 x 50
ERROR You cannot resize a constant size matrix beyond its initial max dimensions
Fatal Error. Aborting at Unhandled Exception
*** The MPI_Abort() function was called after MPI_FINALIZE was invoked.
*** This is disallowed by the MPI standard.
*** Your MPI job will now abort.
[psi3:13270] Local abort after MPI_FINALIZE started completed successfully, but am not able to aggregate error messages, and not able to guarantee that all other processes were killed!

I take suggestions to better pinpoint where this is coming from. Sample inputs are attached:
[vmc_force_jan2020.tar.gz](https://github.com/QMCPACK/qmcpack/files/4099192/vmc_force_jan2020.tar.gz)