Restore volmap tests

[giacomofiorin]

The failed tests were probably just due to the local copy of the NAMD repo being out of sync?

Thanks a million to @HanatoK again for taking the time to fix the regression in the NAMD GridForceGrid class.

[giacomofiorin]

All tests pass minus a GROMACS one (unrelated), merging.

[HanatoK]

There are still precision issues but I don't know why. Here are the results when I ran them locally:

Entering 000_distance-scalable-centerref-dummy ... Success!
Entering 000_distance-scalable-fit-dummy ... Success!
Entering 000_modifycvcs ... Success!
Entering 000_pbc_distance_pairs ... Success!
Entering 000_stringstates ... Success!
Entering 001_carriage_return ... Success!
Entering 002_colvarbias_legacy ... Success!
Entering 003_reinitatoms ... Success!
Entering 004_PDBflags ... Success!
Entering 005_map_total_cvc ...
*** Failure for file test.restart.colvars.traj: see /home/hanatok/HDD/Documents/git/colvars/namd/tests/interface/005_map_total_cvc/test.restart.colvars.traj.diff 
 --> Passes at reduced precision 1e-5
Entering 006_multiple_maps ...
*** Failure for file test.colvars.traj: see /home/hanatok/HDD/Documents/git/colvars/namd/tests/interface/006_multiple_maps/test.colvars.traj.diff 
 --> Passes at reduced precision 1e-3
Entering 007_map_total_internal ... Success!
Entering 008_change_outputName ... Success!
Entering 009_lambda_dynamics ... Success!
There were failed tests.
The following tests are failed, but passed at low precisions:
005_map_total_cvc
006_multiple_maps

[giacomofiorin]

As discussed via chat, this issue is compiler-related (or architecture, in the case of ARM)