Fix failing build (test_coulomb_direct_octions)

[MarcBerneman]

I increased the swap size in order to avoid out-of-memory error 137.
Also, I removed 96 as a parameter to energy.coulomb_direct_neighbor_list because this function doesn't take grid_points as an argument. 96 was given to species, which is not relevant in this test. I also set fractional_coordinates to True as is done here.
I also added the use of a predefined key when adding randomness to R in tpu_test.py. Without this, one of the tests failed at some point due to mere randomness.

[codecov-commenter]

Codecov Report

Merging #287 (b6f95c6) into main (13511dc) will increase coverage by 0.61%.
Report is 22 commits behind head on main.
The diff coverage is 78.78%.

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@@            Coverage Diff             @@
##             main     #287      +/-   ##
==========================================
+ Coverage   82.17%   82.78%   +0.61%     
==========================================
  Files          25       27       +2     
  Lines        4986     5245     +259     
==========================================
+ Hits         4097     4342     +245     
- Misses        889      903      +14     

Files Changed	Coverage Δ
jax_md/elasticity.py	81.46% <ø> (ø)
jax_md/rigid_body.py	94.27% <ø> (ø)
jax_md/simulate.py	91.38% <65.76%> (-5.45%)	⬇️
jax_md/_energy/electrostatics.py	83.68% <83.68%> (ø)
jax_md/_nn/e3nn_layer.py	93.33% <88.23%> (-0.42%)	⬇️
jax_md/_energy/__init__.py	100.00% <100.00%> (ø)
jax_md/_nn/gnome.py	75.28% <100.00%> (+38.20%)	⬆️
jax_md/_nn/nequip.py	90.11% <100.00%> (+0.11%)	⬆️
jax_md/energy.py	91.69% <100.00%> (+1.69%)	⬆️
jax_md/partition.py	88.84% <100.00%> (ø)
... and 2 more

[sschoenholz]

Amazing, thanks so much @MarcBerneman and @abhijeetgangan.