fix bug in isolate code, reenable isolate tests

lib/isolate/frog/natives.js

Index: lib/isolate/frog/natives.js
diff --git a/lib/isolate/frog/natives.js b/lib/isolate/frog/natives.js
index d2543442d0dff1372f9c35ef904c553747b4ba20..62ad76e63f7af6254b94c82dccd00f5514fb9fba 100644
--- a/lib/isolate/frog/natives.js
+++ b/lib/isolate/frog/natives.js
@@ -17,8 +17,9 @@ Function.prototype.wrap$call$0 = function() {
   var isolateContext = $globalState.currentContext;
   var self = this;
   this.wrap$0 = function() {
-    isolateContext.eval(self);
+    var res = isolateContext.eval(self);
     $globalState.topEventLoop.run();
+    return res;
   };
   this.wrap$call$0 = function() { return this.wrap$0; };
   return this.wrap$0;
@@ -31,8 +32,9 @@ Function.prototype.wrap$call$1 = function() {
   var isolateContext = $globalState.currentContext;
   var self = this;
   this.wrap$1 = function(arg) {
-    isolateContext.eval(function() { self(arg); });
+    var res = isolateContext.eval(function() { return self(arg); });
     $globalState.topEventLoop.run();
+    return res;
   };
   this.wrap$call$1 = function() { return this.wrap$1; };
   return this.wrap$1;