Handle blocked I/O of exec'd processes

This is the second part to
https://github.com/containerd/containerd/pull/3361 and will help process
delete not block forever when the process exists but the I/O was
inherited by a subprocess that lives on.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

integration-cli/docker_cli_exec_test.go

@@ -11,7 +11,6 @@ import (
 	"reflect"
 	"runtime"
 	"sort"
-	"strconv"
 	"strings"
 	"sync"
 	"time"
@@ -19,7 +18,6 @@ import (
 	"github.com/docker/docker/client"
 	"github.com/docker/docker/integration-cli/cli"
 	"github.com/docker/docker/integration-cli/cli/build"
-	"github.com/docker/docker/pkg/parsers/kernel"
 	"github.com/go-check/check"
 	"gotest.tools/assert"
 	is "gotest.tools/assert/cmp"
@@ -534,100 +532,3 @@ func (s *DockerSuite) TestExecEnvLinksHost(c *check.C) {
 	assert.Check(c, is.Contains(out, "HOSTNAME=myhost"))
 	assert.Check(c, is.Contains(out, "DB_NAME=/bar/db"))
 }
-
-func (s *DockerSuite) TestExecWindowsOpenHandles(c *check.C) {
-	testRequires(c, DaemonIsWindows)
-
-	if runtime.GOOS == "windows" {
-		v, err := kernel.GetKernelVersion()
-		assert.NilError(c, err)
-		build, _ := strconv.Atoi(strings.Split(strings.SplitN(v.String(), " ", 3)[2][1:], ".")[0])
-		if build >= 17743 {
-			c.Skip("Temporarily disabled on RS5 17743+ builds due to platform bug")
-
-			// This is being tracked internally. @jhowardmsft. Summary of failure
-			// from an email in early July 2018 below:
-			//
-			// Platform regression. In cmd.exe by the look of it. I can repro
-			// it outside of CI.  It fails the same on 17681, 17676 and even as
-			// far back as 17663, over a month old. From investigating, I can see
-			// what's happening in the container, but not the reason. The test
-			// starts a long-running container based on the Windows busybox image.
-			// It then adds another process (docker exec) to that container to
-			// sleep. It loops waiting for two instances of busybox.exe running,
-			// and cmd.exe to quit. What's actually happening is that the second
-			// exec hangs indefinitely, and from docker top, I can see
-			// "OpenWith.exe" running.
-
-			//Manual repro would be
-			//# Start the first long-running container
-			//docker run --rm -d --name test busybox sleep 300
-
-			//# In another window, docker top test. There should be a single instance of busybox.exe running
-			//# In a third window, docker exec test cmd /c start sleep 10  NOTE THIS HANGS UNTIL 5 MIN TIMEOUT
-			//# In the second window, run docker top test. Note that OpenWith.exe is running, one cmd.exe and only one busybox. I would expect no "OpenWith" and two busybox.exe's.
-		}
-	}
-
-	runSleepingContainer(c, "-d", "--name", "test")
-	exec := make(chan bool)
-	go func() {
-		dockerCmd(c, "exec", "test", "cmd", "/c", "start sleep 10")
-		exec <- true
-	}()
-
-	count := 0
-	for {
-		top := make(chan string)
-		var out string
-		go func() {
-			out, _ := dockerCmd(c, "top", "test")
-			top <- out
-		}()
-
-		select {
-		case <-time.After(time.Second * 5):
-			c.Fatal("timed out waiting for top while exec is exiting")
-		case out = <-top:
-			break
-		}
-
-		if strings.Count(out, "busybox.exe") == 2 && !strings.Contains(out, "cmd.exe") {
-			// The initial exec process (cmd.exe) has exited, and both sleeps are currently running
-			break
-		}
-		count++
-		if count >= 30 {
-			c.Fatal("too many retries")
-		}
-		time.Sleep(1 * time.Second)
-	}
-
-	inspect := make(chan bool)
-	go func() {
-		dockerCmd(c, "inspect", "test")
-		inspect <- true
-	}()
-
-	select {
-	case <-time.After(time.Second * 5):
-		c.Fatal("timed out waiting for inspect while exec is exiting")
-	case <-inspect:
-		break
-	}
-
-	// Ensure the background sleep is still running
-	out, _ := dockerCmd(c, "top", "test")
-	assert.Equal(c, strings.Count(out, "busybox.exe"), 2)
-
-	// The exec should exit when the background sleep exits
-	select {
-	case <-time.After(time.Second * 15):
-		c.Fatal("timed out waiting for async exec to exit")
-	case <-exec:
-		// Ensure the background sleep has actually exited
-		out, _ := dockerCmd(c, "top", "test")
-		assert.Equal(c, strings.Count(out, "busybox.exe"), 1)
-		break
-	}
-}