Runner.js should use absolute paths

[Tom Schuster]

This https://github.com/bterlson/es-host-wrapper/blob/master/lib/Runner.js#L15-L20 doesn't work for me on Linux. We end up in right directory, but the binary isn't executed, because it is trying to find the binary in the global path.

args = args || [];
args = args.concat(this.args);
const proc = cp.spawn(this.hostPath, args);
return proc;

[Brian Terlson]

Done :)