This issue was caused by a race between init exits and new exec process
tracking inside the shim. The test operates by controlling the time
between when the shim invokes "runc exec" and when the actual "runc
exec" is triggered. This allows validating that races for shim state
tracking between pre- and post-start of the exec process do not exist.
Relates to https://github.com/containerd/containerd/issues/10589
Signed-off-by: Samuel Karp <samuelkarp@google.com>
