net_uv: child process use net_legacy; recognize NODE_USE_UV=1 env var

lib/child_process.js

@@ -21,7 +21,7 @@
 
 var util = require('util');
 var EventEmitter = require('events').EventEmitter;
-var Stream = require('net').Stream;
+var Stream = require('net_legacy').Stream; // FIXME
 var InternalChildProcess = process.binding('child_process').ChildProcess;
 var constants;
 

src/node.js

@@ -375,7 +375,7 @@
   // backend.
   function translateId(id) {
     if (id == 'net') {
-      return process.useUV ? 'net_uv' : 'net_legacy';
+      return process.useUV || process.env.NODE_USE_UV ? 'net_uv' : 'net_legacy';
     } else {
       return id;
     }