process.env.NODE_ENV can not pass to child process

[snayan]

when i use jest.run to run my tests, thread-loader can not pass process.env.NODE_ENV to child process. i print process.env.NODE_ENV in main process and child process, such as

explicit pass env，child process will get the correct process.env.NODE_ENV

this.worker = childProcess.spawn(process.execPath, [].concat(sanitizedNodeArgs).concat(workerPath, options.parallelJobs), {
    detached: true,
    stdio: ['ignore', 'pipe', 'pipe', 'pipe', 'pipe'],
    env: process.env
 });