Do not normalize types in the api extraction phase.

In summary this commit:

  * drops type normalization in api phase but keeps dealiasing
  * fixes #736 and marks corresponding test as passing

I discussed type normalization with @adriaanm and according to him
sbt shouldn't call that method. The purpose of this method to
convert to a form that subtyping algorithm expects. Sbt doesn't need
to call it and it's fairly expensive in some cases.

Dropping type normalization also fixes #726 by not running into
stale cache in Scala compiler problem described in SI-7361.

compile/interface/src/main/scala/xsbt/API.scala

@@ -312,9 +312,13 @@ final class API(val global: CallbackGlobal) extends Compat
 	private def processType(in: Symbol, t: Type): xsbti.api.Type = typeCache.getOrElseUpdate((in, t), makeType(in, t))
 	private def makeType(in: Symbol, t: Type): xsbti.api.Type =
 	{
-		def dealias(t: Type) = t match { case TypeRef(_, sym, _) if sym.isAliasType => t.normalize; case _ => t }
 
-		dealias(t) match
+		val dealiased = t match {
+			case TypeRef(_, sym, _) if sym.isAliasType => t.dealias
+			case _ => t
+		}
+
+		dealiased match
 		{
 			case NoPrefix => Constants.emptyType
 			case ThisType(sym) => new xsbti.api.Singleton(thisPath(sym))