1. What happened
[New Scripting Runtime] While debugging, Visual Studio Code doesn't break at breakpoints and freezes the Editor after the debugger is detached.
The same scenario works fine for the legacy runtime.

2. How we can reproduce it using the example you attached
- Open scene 1
- Open TestScript.cs with VSCode
- Put breakpoint on line 9 : Debug.Log("asdf");
- Start debugger for Unity Editor config (I'm using this ext: https://marketplace.visualstudio.com/items?itemName=Unity.unity-debug)
- Switch to Editor and Play
>>> Notice that Console reports 'asdf' but the breakpoint wasn't hit.
- Exit Play mode
- Stop debugger
- Return to Editor and wait for a few seconds (usually about 5-10 seconds).
>>> Editor stops responding