tests: client: enable a batch of integration tests for wcow

WIP

- [x] `testStdinClosed`

Addressing moby#4485

Signed-off-by: Anthony Nandaa <profnandaa@gmail.com>

client/client_test.go

@@ -628,12 +628,13 @@ func testHostnameSpecifying(t *testing.T, sb integration.Sandbox) {
 
 // moby/buildkit#614
 func testStdinClosed(t *testing.T, sb integration.Sandbox) {
-	integration.SkipOnPlatform(t, "windows")
 	c, err := New(sb.Context(), sb.Address())
 	require.NoError(t, err)
 	defer c.Close()
 
-	st := llb.Image("busybox:latest").Run(llb.Shlex("cat"))
+	imgName := integration.UnixOrWindows("busybox:latest", "nanoserver:latest")
+	cmdStr := integration.UnixOrWindows("cat", "cmd /C more")
+	st := llb.Image(imgName).Run(llb.Shlex(cmdStr))
 
 	def, err := st.Marshal(sb.Context())
 	require.NoError(t, err)