don't mangle names of setters/getters

lib/scope.js

@@ -325,9 +325,13 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(){
             return true;        // don't descend again in TreeWalker
         }
         if (node instanceof AST_Scope) {
+            var p = tw.parent();
+            var is_setget = p instanceof AST_ObjectSetter || p instanceof AST_ObjectGetter;
             var a = node.variables;
             for (var i in a) if (HOP(a, i)) {
-                a[i].mangle();
+                var symbol = a[i];
+                if (!(is_setget && symbol instanceof AST_SymbolLambda))
+                    symbol.mangle();
             }
             return;
         }