Fix browser freezing when executing child debug

[alvsan09]

What it does

Fixes: #11387

Fixes an infinite loop that was triggered when attempting
to resolve a parent console.

How to test

Copying test procedure from: #9613

1. Clone this test repo into Theia and make sure the vscode-js-debug extension is installed in Theia.
2. Start a debugging session with the contained Launch Program configuration.
3. Child processes will now be shown as a tree in the threads view.
4. Start a second debugging session with the same configuration
5. Another tree will appear in the threads view and you can switch between the different debug consoles.

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

[msujew]

Thanks! I can confirm that the issue exists on master and is addressed by this change nicely 👍

[alvsan09]

Thanks! I can confirm that the issue exists on master and is addressed by this change nicely +1

Thanks @msujew !