Description of problem

Sometimes the container's IO's stdout will hang, and at the same time the stdout
will go on outputting when you hit the keyboard to input any character.

The same issue has been fixed in kata-proxy kata-containers/proxy#91
but hasn't been forwarded to kata builtin proxy.

Expected result

(replace this text with an explanation of what you thought would happen)

Actual result

(replace this text with details of what actually happened)

(replace this text with the output of the kata-collect-data.sh script, after
you have reviewed its content to ensure it does not contain any private
information).