No need to check if process is alive. Fixes #16487. Refs #16317.

There's no need to check for a live process because since we're changing flags on the file descriptor, if it's not none, we
reset the flags.
Merge pull request #16569 from s0undt3ch/hotfix/vt-freezes-on-osx

No need to check if process is alive. Fixes #16487. Refs #16317.