Fix bogus assertion.

R=dcarney@chromium.org
BUG=

Review URL: https://chromiumcodereview.appspot.com/12296008

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13684 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/heap.cc

@@ -3600,7 +3600,9 @@ MaybeObject* Heap::AllocateExternalStringFromAscii(
     return Failure::OutOfMemoryException(0x5);
   }
 
+#ifndef ENABLE_LATIN_1
   ASSERT(String::IsAscii(resource->data(), static_cast<int>(length)));
+#endif  // ENABLE_LATIN_1
 
   Map* map = external_ascii_string_map();
   Object* result;