runtime: Debugger.Launch doesn't work correctly on coreclr on Windows

Repro:

using System;
using System.Diagnostics;

public class Test
{
    public static void Main()
    {
        Console.WriteLine("1");
        Console.WriteLine("2");
        Debugger.Launch();
        Console.WriteLine("3");
        Console.WriteLine("4");
    }
}

With .NET Framework, I can compile this, run it from the console, and the Debugger.Launch pops the attach dialog asking which VS I want to use and which debugging engine to employ. I’m then in the debugger broken into the app on the Launch line, and I can successfully F10 to step to the WriteLine for “3” and “4”.

With .NET Core 2.0 (built with the latest source), the same thing happens, up until the debugger breaking in. VS opens, but I have to manually hit the pause button to break into the app. Then I find myself on the Launch line, but neither F5 nor F10 work successfully; instead, they start running the app again, but no forward progress is made, and breaking in again reveals being on the same line, with this stack:

 	ntdll.dll!NtWaitForMultipleObjects()	Unknown
 	KernelBase.dll!WaitForMultipleObjectsEx()	Unknown
 	[Managed to Native Transition]	
>	tmpapp.dll!Test.Main() Line 10	C#
 	[Native to Managed Transition]	
 	CoreRun.exe!00007ff68c9f2fa3()	Unknown
 	CoreRun.exe!00007ff68c9f33dc()	Unknown
 	CoreRun.exe!00007ff68c9fc149()	Unknown
 	kernel32.dll!BaseThreadInitThunk()	Unknown
 	ntdll.dll!RtlUserThreadStart()	Unknown

That’s the case with both VS2015 and VS2017, and with selecting the managed CoreCLR debug engine.

Am I missing some component that’s supposed to make this work?