Supporting splat at right-hand-side of masgn

[soutaro]

c, t, m, lib = *split_method_id(id)

Even though having * here doesn't make much sense.

[soutaro]

class Foo
  def to_ary = [1,2,3]
end

a, b, c = Foo.new     # Foo#to_ary is used to convert the single object to an array, and the value of the expression is a Foo object
a, b, c = *Foo.new    # The right hand side is [Foo.new], and the value of the expression is an array