Test: variable substition in launch.json and tasks.json

[isidorn]

• any os @gregvanl
• any os @jrieken

complexity: 3

We have consolidated our variable substition between debug and tasks into a configurationResolverService - #8754. Quickly verify:

• Simple variables get replaced inside launch.json and tasks.json as descirbed here
• You can reference environment variables inside your launch.json and tasks.json by using ${env.NAME} syntax
• You can reference vscode settings inside your launch.json and tasks.json by using ${config.NAME} syntax
• You can reference interactive variables inside your launch.json by using ${command.PickProcess}

[gregvanl]

Tested on Windows 7.