VSTHRD003 False positive in top-level statements

[NinjaCross]

Bug description

The VSTHRD003 is triggered when using a combination of Task.Run and Task.WhenAny in a "top-level statements" (programs without Main methods) console app

Repro steps

This "top-level statements" code will trigger VSTHRD003

using var cts = new CancellationTokenSource();
      
var loopTask = Task.Run(
    async () =>
    {
        // DO SOMETHING...
    },
    cts.Token);

var serverTask = Task.Run(
    async () =>
    {
      // DO SOMETHING...
    },
    cts.Token);

var exitTask = Task.Run(
    () =>
    {
        Console.WriteLine("Press any key to exit");
        Console.ReadKey();
        cts.Cancel();
    },
    cts.Token);

await Task.WhenAny(loopTask, serverTask, exitTask);  /// VSTHRD003 is triggered here !
Console.WriteLine("Exited");

This traditional console app, on the other hand, does not trigger VSTHRD003

public static class Program
{
    public static async Task Main(string[] args)
    { 
        using var cts = new CancellationTokenSource();
      
        var loopTask = Task.Run(
            async () =>
            {
                // DO SOMETHING...
            },
            cts.Token);

        var serverTask = Task.Run(
            async () =>
            {
              // DO SOMETHING...
            },
            cts.Token);

        var exitTask = Task.Run(
            () =>
            {
                Console.WriteLine("Press any key to exit");
                Console.ReadKey();
                cts.Cancel();
            },
            cts.Token);

        await Task.WhenAny(loopTask, serverTask, exitTask);  /// VSTHRD003 is NOT triggered here !
        Console.WriteLine("Exited");
    }
}

Expected behavior

VSTHRD003 should not be triggered in this scenario

Actual behavior

VSTHRD003 is triggered in this scenario, and it shouldn't

• Version used: 17.12.19.10947