Debugging using redirected input from file - The handle is invalid.

## Environment data
.NET Command Line Tools (2.1.4)

Product Information:
Version: 2.1.4
Commit SHA-1 hash: 5e8add2190

Runtime Environment:
OS Name: Mac OS X
OS Version: 10.13
OS Platform: Darwin
RID: osx.10.12-x64
Base Path: /usr/local/share/dotnet/sdk/2.1.4/

Microsoft .NET Core Shared Framework Host

Version : 2.0.5
Build : 17373eb129b3b05aa18ece963f8795d65ef8ea54

VS Code version: 1.22.2
C# Extension version: 1.14.0

## Steps to reproduce

1. Create a program which reads from standard input
` String textLine = Console.ReadLine();
`
2. Set up launch.json

>{
"name": ".NET Core Launch (console)",
"type": "coreclr",
"request": "launch",
"preLaunchTask": "build",
// If you have changed target frameworks, make sure to update the program path.
"program": "${workspaceFolder}/bin/Debug/netcoreapp2.0/moving-elephants.dll",
"args": ["