setAlphaField crashes boundary condition related

Summary

setAlphaField crashes if used in combination with the inletOutlet boundary condition. Most likely also with others, but these are really common for alpha fields. This error does not exist in the v1812 and was hence introduced by some change. Tested in v2006

Steps to reproduce

Change one of the boundary conditions to inletOutlet

`Reading field alpha.water

--> FOAM FATAL ERROR:

request for surfaceScalarField phi from objectRegistry region0 failed
available objects of type surfaceScalarField are

1(mag(delta))

From const Type& Foam::objectRegistry::lookupObject(const Foam::word&, bool) const [with Type = Foam::GeometricField<double, Foam::fvsPatchField, Foam::surfaceMesh>]
in file /home/bloerb/OpenFOAM/OpenFOAM-v2006/src/OpenFOAM/lnInclude/objectRegistryTemplates.C at line 463.

FOAM aborting `