Test: running DA in extension host

[weinand]

Test for #45129:

Please note: since we do not ship this feature in March there is no need to have this tested by more than one dev.

• anyOS: @isidorn

Complexity: 3

Testing:

• Checkout the "cleanupDA" branch and build
• run VS Code from branch
• verify that debugging works correctly for both values of the user setting debug.extensionHostDebugAdapter.
• try this for the C++ or Python debug extension

[isidorn]

I have verified that debugging works for our vscode smoke test express and for a simple hello world python app. For both values of debug.extensionHostDebugAdapter