[jest-dev-server] read from server's stdout to prevent buffer from filling up

[tiger31]

Summary

Fixes problem with filling up processes buffer.
If process created by jest-dev-server with debug=false option writes something to stdout, it will stop responding after some time. Reading from stdout and doing nothing with it fixes the problem

Test plan

Run any process with setup function from jest-dev-server with both debug=true and false. Should spawn process in both cases

[UziTech]

Thanks! 💯