STC: callable (closure) property from super class

GROOVY-5881, GROOVY-6324, GROOVY-9418

Consider the following:

abstract class A {
  Closure func = { x -> x }
}
class C extends A {
  Closure proc = { -> }
  @CompileStatic test() {
    func(123)
    proc()
  }
}

print(new C().test())

STC is happy with "proc()" but errors on "func(123)". If a variable expression can be called without ".call" it should not matter the source of the variable. Both method call expressions work fine without STC.