Use LAPLACIAN = False in tx2_3v2

[gustavo-marques]

MOM_interface always sets LAPLACIAN = True (see here). However, in the workhorse configurations (tx2_3v2), the Laplacian coefficient is zero, so setting LAPLACIAN = True has no effect.

Let's set LAPLACIAN = False for the tx2_3v2 configurations to avoid confusion, which will not change the answers.

[alperaltuntas]

@gustavo-marques Is this needed for beta05? I an tentatively adding it to the milestone, but feel free to remove it if it's not needed.

[alperaltuntas]

As per #216 comment by @gustavo-marques , this issue is no longer relevant.