revert(Shard): "fix missing child_process silent option of Shard to allow listening to output" (#4707)

This reverts commit 58d1589a55.

src/sharding/Shard.js

@@ -115,7 +115,6 @@ class Shard extends EventEmitter {
         .fork(path.resolve(this.manager.file), this.args, {
           env: this.env,
           execArgv: this.execArgv,
-          silent: true,
         })
         .on('message', this._handleMessage.bind(this))
         .on('exit', this._exitListener);