* 'get_atomic_ent_value()' is a wrapper, which tries to unify the different kind of initalizers by wastefully creating nodes on demand.
  It had only a single user, which tried to use it for method entities, which does not work anymore (see 3rd bullet point).
* 'set_atomic_ent_value()' is a thin and unnecessary wrapper to set a const node initializer.
* 'is_atomic_entity()' classifies entities having (among primitive and pointer types) method type as having an atomic initializer.
  They do not for a long time (was an address of itself).
  Except for the two functions above, this function is unused.
* 'Atomic' is a misnomer and should rather be 'scalar'.