Don't force symbol denotation when taking fingerprint.

Author: odersky

src/dotty/tools/dotc/config/Config.scala

@@ -4,7 +4,7 @@ object Config {
 
   final val cacheMembersNamed = true
   final val cacheAsSeenFrom = true
-  final val useFingerPrints = true
+  final val useFingerPrints = true // note: it currently seems to be slightly faster not to use them! my junit test: 548s without, 560s with.
   final val cacheMemberNames = true
   final val cacheImplicitScopes = true
 

src/dotty/tools/dotc/core/SymDenotations.scala

@@ -1384,7 +1384,7 @@ object SymDenotations {
       var fp = FingerPrint()
       var e = info.decls.lastEntry
       while (e != null) {
-        fp.include(e.sym.name)
+        fp.include(e.name)
         e = e.prev
       }
       var ps = classParents