cmd/recover doesn't work for programs that require a TTY / stdin

[dhermes]

What happened:

$ go build -o main cmd/recover/main.go
$ ./main -verbose python
recover: "python" resolved to "/Users/dhermes/.pyenv/shims/python"
^Crecover: received SIGINT (interrupt) while sub process is running, killing sub process
recover: sub process exit: signal: interrupt

What you expected to happen:

$ ./main -verbose python
recover: "python" resolved to "/Users/dhermes/.pyenv/shims/python"
Python 3.7.3 (default, Mar 27 2019, 08:18:46) 
[Clang 10.0.1 (clang-1001.0.46.3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> 
...

How to reproduce it (as minimally and precisely as possible):

See above

Anything else we need to know?:

This is not urgent or even necessarily a feature, but we could early exit if we detect TTY / stdin is needed.

Environment:

• go-sdk version: master at 9b8efca (I ran this as part of Update cmd/recover to only resolve bin on PATH once #138, so it's really at b55dead)
• go version (e.g go version): go version go1.13 darwin/amd64
• OS (e.g: cat /etc/os-release):

  $ sw_vers
  ProductName:    Mac OS X
  ProductVersion: 10.14.6
  BuildVersion:   18G103