s/normaliz/simplifi/ in tryCompiletimeConstantFold

This change fixes an issue with tests/pos/i8449.scala. That test does
not compiler on master when using `case Any =>` instead of `case _ =>`
in the Fibonacci match type. The changes made in this PR expose that bug
by parsing the latter into the former.

Author: OlivierBlanvillain

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

@@ -4094,12 +4094,12 @@ object Types {
         def natValue(tp: Type): Option[Int] = intValue(tp).filter(n => n >= 0 && n < Int.MaxValue)
 
         def constantFold1[T](extractor: Type => Option[T], op: T => Any): Option[Type] =
-          extractor(args.head.normalized).map(a => ConstantType(Constant(op(a))))
+          extractor(args.head.simplified).map(a => ConstantType(Constant(op(a))))
 
         def constantFold2[T](extractor: Type => Option[T], op: (T, T) => Any): Option[Type] =
           for {
-            a <- extractor(args.head.normalized)
-            b <- extractor(args.tail.head.normalized)
+            a <- extractor(args.head.simplified)
+            b <- extractor(args.tail.head.simplified)
           } yield ConstantType(Constant(op(a, b)))
 
         trace(i"compiletime constant fold $this", typr, show = true) {