data: prevent mpi comm with single rank

[mloubout]

This is not the best solution and ideally we would fix the array interface.

Currently, things like a.data[:] *= s with s scalar will create s * a.data` then broadcast it to all ranks (eeech) even with one rank. Temporary patch until we fix it properly.

[JDBetteridge]

All nitpicks, if urgent address later

[codecov]

Codecov Report

Attention: Patch coverage is 90.00000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 91.32%. Comparing base (217a3af) to head (03ff042).
Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
devito/data/data.py	83.33%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2685      +/-   ##
==========================================
- Coverage   92.02%   91.32%   -0.70%     
==========================================
  Files         245      245              
  Lines       49093    49093              
  Branches     4322     4322              
==========================================
- Hits        45176    44835     -341     
- Misses       3216     3538     +322     
- Partials      701      720      +19     

Flag	Coverage Δ
pytest-gpu-aomp-amdgpuX	72.51% <50.00%> (ø)
pytest-gpu-nvc-nvidiaX	?

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