Fix handling of context creation failure since r13978.

R=jkummerow@chromium.org
TEST=fast/js/concat-large-strings-crash.html

Review URL: https://codereview.chromium.org/12702008

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13998 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/bootstrapper.cc

@@ -303,9 +303,9 @@ Handle<Context> Bootstrapper::CreateEnvironment(
     v8::ExtensionConfiguration* extensions) {
   HandleScope scope(isolate_);
   Genesis genesis(isolate_, global_object, global_template, extensions);
-  Handle<Object> context(isolate_->global_handles()->Create(*genesis.result()));
-  Handle<Context> env = Handle<Context>::cast(context);
-  if (!env.is_null()) {
+  if (!genesis.result().is_null()) {
+    Handle<Object> ctx(isolate_->global_handles()->Create(*genesis.result()));
+    Handle<Context> env = Handle<Context>::cast(ctx);
     if (InstallExtensions(env, extensions)) {
       return env;
     }