Add regression test for LAMMPS dump reader (in VisItBridge) for multiple time steps
The LAMMPS dump format supports holding multiple timesteps, and the VisIt reader can read through these timesteps. There was a bug in the VisIt Bridge that prevented all but the first timestep to be read. This problem was fixed in MRs !6454 (merged) and visitbridge!101 (merged). The regression test currently only tests a file with one timestep. A regression test to test for multiple time steps should be added.
Here is a small, simple LAMMPS dump file with 2 timesteps.