fix the --no-pivot flag being ignored by ctr tasks start

Signed-off-by: Iceber Gu <wei.cai-nat@daocloud.io>

cmd/ctr/commands/tasks/tasks_windows.go

@@ -29,6 +29,8 @@ import (
 	"github.com/urfave/cli"
 )
 
+var platformStartFlags = []cli.Flag{}
+
 // HandleConsoleResize resizes the console
 func HandleConsoleResize(ctx gocontext.Context, task resizer, con console.Console) error {
 	// do an initial resize of the console