Fix condition for lambda abstracting in Namer

The previous condition could make a (derived) type a * type
for a little while even though it had type parameters. This
loophole caused collection/generic/MapFactory.scala and with
it compile-stdlib to fail.

Author: odersky

src/dotty/tools/dotc/typer/Namer.scala

@@ -935,7 +935,7 @@ class Namer { typer: Typer =>
     //val toParameterize = tparamSyms.nonEmpty && !isDerived
     //val needsLambda = sym.allOverriddenSymbols.exists(_ is HigherKinded) && !isDerived
     def abstracted(tp: Type): Type =
-      if (tparamSyms.nonEmpty && !isDerived) tp.LambdaAbstract(tparamSyms)
+      if (tparamSyms.nonEmpty && !tp.isHK) tp.LambdaAbstract(tparamSyms)
       //else if (toParameterize) tp.parameterizeWith(tparamSyms)
       else tp