Describe the bug

Running e.g. precomputed-seissol/tpvloh1-fused with a single-simulation build and an 8-simulation build yields different results for the first simulation.

Expected behavior

The simulations that are simulated should always yield the same results.

To Reproduce

Steps to reproduce the behavior:

1. Which version do you use? Current master, 6e09237
2. Which build settings do you use? GCC 14.2
3. On which machine does your problem occur? My laptop.
4. Provide parameter/material files. Take precomputed-seissol/tpvloh1-fused

Screenshots/Console output

(can provide if needed; the additional context should explain enough already)

Additional context

The problem is pretty clearly due to how the point sources are distributed right now—it happens in a round-robin fashion.

I.e. a single simulation just gets all point sources. In the multisim case with N simulations; point source 0 goes to simulation 0, 1 goes to 1, 2 to 2, 3 to 3,..., and then N goes to simulation 0, (N+1) to 1, ..., 2N to 0, (2N+1) to 1, etc.

Thus, it's obvious that there will be different results—but it's really unintuitive if you just run it with different SeisSols.