postProcess with cyclicACMI patches
Summary
Run the oscillatingACMI2D tutorial with some e.g. isoSurface functionObject as ``postProcess``` and it will crash since the pointMesh gets cleared out but the pointField (from volPointInterpolation) does not.
Possible fixes
In polyMesh::readUpdate make sure to update pointMesh (or MeshObject) in general instead of deleting it.