OCI Modifiers for Windows

Signed-off-by: John Howard <jhoward@microsoft.com>

Needed for the containerd work on Windows and integrating the
oci package from containerd into moby.

No longer sets defaults for
 - .Process.ConsoleSize
 - .Windows.IgnoreFlushesDuringBoot
 - .Windows.Network.AllowUnqualifiedDNSQuery

Adds helper functions and tests for
 - WithWindowsIgnoreFlushesDuringBoot
 - WithWindowNetworksAllowUnqualifiedDNSQuery

Updates `ctr run` on Windows to use the new helper functions,
ConsoleSize is already handled.

cmd/ctr/commands/run/run_windows.go

@@ -64,6 +64,8 @@ func NewContainer(ctx gocontext.Context, client *containerd.Client, context *cli
 			opts = append(opts, oci.WithRootFSPath(""))
 		} else {
 			opts = append(opts, oci.WithDefaultSpec())
+			opts = append(opts, oci.WithWindowNetworksAllowUnqualifiedDNSQuery())
+			opts = append(opts, oci.WithWindowsIgnoreFlushesDuringBoot())
 		}
 		opts = append(opts, oci.WithEnv(context.StringSlice("env")))
 		opts = append(opts, withMounts(context))