node: fix #7841 by overlooking the spare sourceline

See **title** :)
i tested in my node(v0.11.14-pre) and it prints:
```
/Users/yorkie/workspace/test.js:22
/**
^^^
SyntaxError: Unexpected token ILLEGAL
    at exports.runInThisContext (vm.js:69:16)
    at Module._compile (module.js:432:25)
    at Object.Module._extensions..js (module.js:467:10)
    at Module.load (module.js:349:32)
    at Function.Module._load (module.js:305:12)
    at Function.Module.runMain (module.js:490:10)
    at startup (node.js:124:16)
    at node.js:807:3
```
what's problem with this?