[addr me: Self*] CHECK failure when used in interface method

[zygoloid]

Testcase:

package Foo api;

interface Container {
  fn Add[addr me: Self*](x: i32);    
}
fn Add[T:! Container](p: T*, y: i32) {      
  (*p).Add(y);
}

class X {
  impl as Container {                                                 
    fn Add[addr me: Self*](x: i32) { Print("Add {0}", x); }
  }
}
fn Main() -> i32 {
  var x: X = {};
  Add(&x, 5);
  return 0;
}

... results in:

CHECK failure at explorer/interpreter/interpreter.cpp:274: v->kind() == Value::Kind::LValue

Looks like we currently only call set_is_field_addr_me_method for direct calls on a NominalClassType. Presumably we should set that for all simple and compound member accesses where the target is a method and we're not forming a member name expression.