src: remove unused comment
src: remove unused comment

Now that Context::New(Isolate*) returns Local, the removed comment is
no longer applicable that there is a Persistent which will need to be
disposed.

dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node