Fixed inconsistent abstract constructor assignability and instantiation checks

[bgenia]

Fixes #59890

I tried to make abstract/concrete constructor relation behave similarly to other subtyping relations:

1. Abstract/concrete constructor assignability is now checked for each individual signature
2. Abstract constructor instantiation is now checked after signature resolution only for the resolved signature

The second change makes it possible to instantiate concrete constructors with abstract overloads if concrete overload is resolved.

type MixedConstructor =
  & (new (kind: "concrete") => void)
  & (abstract new (kind: "abstract") => void)

declare const MixedConstructor: MixedConstructor

new MixedConstructor("concrete") // ok
new MixedConstructor("abstract") // error

This is done mainly to eliminate inconsistencies between type relations and instantiation checks (signatures not actually being abstract but being treated as such) and make this behavior more intuitive.