NYC or spawn-wrap bug when used with execArgv

It seems that either NYC or spawn-wrap is preventing ipc channel creation, but only when an execArgv option is provided.

To reproduce:

1. Clone this repo
2. npm install
3. npm test

You will see the simple test pass when used normally, but when wrapped with NYC, it fails.

If you uncomment the execArgv: ['--no-deprecation'] line in index.js, it will pass, even with NYC.

The failure prints a stacktrace indicating that process.send does not exist in the child process. This indicates that, while the correct child process was forked, it happened without an IPC channel.

Seems like a bug.