Fix test

Author: odersky

tests/neg/named-tuples-3.check

@@ -0,0 +1,4 @@
+-- Error: tests/neg/named-tuples-3.scala:7:16 --------------------------------------------------------------------------
+7 |val p: Person = f  // error
+  |                ^
+  |                Malformed NamedTuple: names must be string types, but Int was found.

tests/neg/named-tuples-3.scala

@@ -1,7 +1,7 @@
 import language.experimental.namedTuples
 
-def f: NamedTuple.NamedTuple[(Int, Any), (Int, String)] = ??? // error
+def f: NamedTuple.NamedTuple[(Int, Any), (Int, String)] = ???
 
 type Person = (name: Int, age: String)
 
-val p: Person = f
+val p: Person = f  // error