Fix ctr run for Windows containers

1. Fixes bugs in ctr run that were introduced by 1d9b969
2. Adds support for the --isolated flag that runs Windows HyperV
cotainers instead of process isolated containers on Windows.

Signed-off-by: Justin Terry (VM) <juterry@microsoft.com>

runtime/v2/runhcs/service.go

@@ -49,7 +49,6 @@ import (
 )
 
 const (
-	runhcsBinary      = "runhcs"
 	runhcsShimVersion = "0.0.1"
 )