Resolve bound type parameters from generic superclass during path lookup

[HertzDevil]

Fixes #10834.

Also fixes part of #5243. The code

class Foo(A)
  def initialize(@value : A)
  end
end

class Bar(B) < Foo(B)
end

Bar(Int32).new(25)

will now work as long as Bar's generic arguments are provided; that is, Foo#initialize will correctly use Int32 as the restriction instead of the formal argument B. (Bar.new doesn't know that A is a free variable, so Bar.new(25) still fails.)

[straight-shoota]

@HertzDevil ping ⬆️

[straight-shoota]

@HertzDevil There are multiple specs failures apparently related to this change.