add back resolved for Alias

Author: chenghao-intel

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/namedExpressions.scala

@@ -112,6 +112,8 @@ case class Alias(child: Expression, name: String)(
   extends NamedExpression with trees.UnaryNode[Expression] {
 
   override type EvaluatedType = Any
+  // Alias(Generator, xx) need to be transformed into Generate(generator, ...)
+  override lazy val resolved = childrenResolved && !child.isInstanceOf[Generator]
 
   override def eval(input: Row): Any = child.eval(input)