Description of problem

Latest shimv2 publishes an event to containerd used ttrpc instead
of using containerd binary, thus shimv2 shouldn't call os.Exit to
terminate the shim's life, but close the context on shutdown so that
events and other resources have hit the defers.

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).