Test: Auto attach for Node-Debug

[weinand]

Test for #42521:

• windows @sbatten
• macOS @chrmarti
• linux @aeschli

Complexity: 2

In this milestone we've added an "Auto Attach" feature to VS Code's Node.js debugger. If enabled the node debugger (both protocols) automatically attaches to node.js processes that are launched in debug mode in VS Code's integrated terminal.

To enable the feature either use the "Toggle Auto Attach" action or if the Node Debug is already activated use the "Auto Attach" status bar item.

Whether a process is in debug mode is guessed by analysing the program arguments. Currently we detect the patterns --inspect, --inspect-brk, --inspect-port, --debug, --debug-brk, --debug-port (all optionally followed by a '=' and a port number).

Please note that this feature does not yet work for terminal multiplexers (where launched processes are not children of VS Code's integrated terminal.

Test:

• verify that the feature is turned off initially
• enable the feature
• verify that the node debugger attaches to node.js programs if they are launched with the various debug flags from above ("inspect" for node.js >= 6.3, "debug" for node.js < 8.0).
• verify that disabling the feature stops the auto-attach behavior

On Windows watch out for too many or stuck 'wmic' processes that cripple performance.

[weinand]

Checking off for @sbatten since he did testing (despite the fact that he found an fundamental issue).