Can't open, rename or delete files that contains ":" on linux (fix microsoft/vscode-remote-release#4227)

Dispose all Disposables from tests

Fixes #113807: Fixed not to skip determination of option type starting with "_"

- use workspace configuration disposables

Co-authored-by: NBenjamin Pasero <benjpas@microsoft.com>

This reverts commit 01c6003c.

* Fixes #109127

* manually compute content offset in case the window has a border

These tests were disable due to some occasional failures on build machines. This PR enables them but with flakySuite while I track down possible causes of these failures