This should hold now that no more empty spill infos are generated for Phi arguments.

This removes the last attributes from struct arch_env_t.

be: Move the info about the register classes and registers struct the arch_env_t into struct arch_isa_if_t.

Just use the selected isa interface directly.

In particular create Keeps for mode_T nodes in one go instead of adding one Proj to the Keep after another.

The only user should be an arch_add_irn_flags() instead.
It was harmless though, because no other flags were set.

Rematerialisations involving multiple nodes and Projs (e.g. Proj->Load) got miscounted.
Now a rematerialization always counts as 1.

The node was just created, so it is not scheduled.

Move the values interfere function to belive.h, move the inline
implementation into belive.c

- Remove value_dominates_intrablock()/value_strictly_dominates_intrablock()
  and use sched_comes_before() instead
- Use bool instead of int return types.
- Assert that we don't check if a node interferes with itself as that is
  nearly always a bug in the code.

- the linked lists are introduced to get a deterministic order
- irnodehashmap instead of set should be slightly faster