Remove references to ProductN from Definitions.scala

Author: OlivierBlanvillain

compiler/src/dotty/tools/dotc/core/Definitions.scala

@@ -680,7 +680,6 @@ class Definitions {
   def FunctionClassPerRun = new PerRun[Array[Symbol]](implicit ctx => ImplementedFunctionType.map(_.symbol.asClass))
 
   lazy val TupleType = mkArityArray("scala.Tuple", MaxTupleArity, 2)
-  lazy val ProductNType = mkArityArray("scala.Product", MaxTupleArity, 0)
 
   def FunctionClass(n: Int)(implicit ctx: Context) =
     if (n < MaxImplementedFunctionArity) FunctionClassPerRun()(ctx)(n)
@@ -698,7 +697,6 @@ class Definitions {
     else FunctionClass(n).typeRef
 
   private lazy val TupleTypes: Set[TypeRef] = TupleType.toSet
-  private lazy val ProductTypes: Set[TypeRef] = ProductNType.toSet
 
   /** If `cls` is a class in the scala package, its name, otherwise EmptyTypeName */
   def scalaClassName(cls: Symbol)(implicit ctx: Context): TypeName =