src: update NODE_MODULE_VERSION to 57

Node.js 8.0.0 is API/ABI forward-compatible with V8 6.0.
The current module version is 55 and corresponds to V8 5.8. This
increments the number by two to prevent incompatibility with modules
compiled from Node master.

PR-URL: https://github.com/nodejs/node/pull/12995


Reviewed-By: Ali Ijaz Sheikh <ofrobots@google.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>