Improve test for SI-5125.

Uncomment a line, as was the intent.

Author: retronym

test/files/run/t5125b.scala

@@ -6,7 +6,7 @@ class C1 {
 class C2 {
   @scala.annotation.varargs
   def f(values:String*) = println("Calling C2.f(): "  + values)
-  // def g(): String => Int = s => s.hashCode
+  def g(): String => Int = s => s.hashCode
 
   class C3 {
     @scala.annotation.varargs