Summary:Shelling out on win32 does not properly escape the command due to c3bb4b1aa5/lib/child_
This patch ensures a proper lineNumber before continuing, similar to how we check that the fileName passed exists.
**Test plan**
On platform `win32` or given appropriate testing changes to `launchEditor.js`...
With the following `request-bad` file:
```
GET /open-stack-frame HTTP/1.1
Host: 127.0.0.1:8081
Proxy-Connection: keep-alive
Cache-Control: max-age=0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/48.0.2564.116 Safari/537.36
Accept-Encoding: gzip, deflate, sdch
Accept-Language: en-US,en;q=0.8
Content-Length: 64
{"file":"C:\\Windows\\system.ini","lineNumber":"123\" && calc"}
```
`$ nc localhost 8081 < request-bad`
Observe that before this patch `calc` would launch and afte
Closes https://github.com/facebook/react-native/pull/6299
Differential Revision: D3012074
Pulled By: davidaurelio
fb-gh-sync-id: cbc7b6e5c60529a289c0989a95593a322333ba5d
shipit-source-id: cbc7b6e5c60529a289c0989a95593a322333ba5d
ab61a1fbac