[6.0] Serialize SFunc in TypeSerializer

[kushti]

This PR is adding higher-order lambdas support in serialization, thus making them useful.

Example:

{
   val c = Coll(Coll(1))
   def fn(xs: Coll[Int]) = {
     val inc = { (x: Int) => x + 1 }
     def apply(in: (Int => Int, Int)) = in._1(in._2)
     val ys = xs.map { (x: Int) => apply((inc, x)) }
     ys.size == xs.size && ys != xs
   }
   c.exists(fn)
 }

Close #847

[aslesarenko]

LGTM, but also see the comment

[aslesarenko]

please clarify "identical but other".

[kushti]

done, // todo: 6.0: replace 1008 check with identical behavior but other opcode, to activate
// ReplacedRule(1008 -> new opcode) during 6.0 activation