Add launch config for running the test suite with the vscode debugger

.vscode/launch.json

@@ -0,0 +1,20 @@
+{
+  // Use IntelliSense to learn about possible attributes.
+  // Hover to view descriptions of existing attributes.
+  // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "protocol": "inspector",
+      "type": "node",
+      "request": "launch",
+      "name": "Mocha Tests",
+      "program": "${workspaceFolder}/node_modules/mocha/bin/_mocha",
+      "args": ["--timeout", "9999999999"],
+      "internalConsoleOptions": "openOnSessionStart",
+      "skipFiles": [
+        "<node_internals>/**" // Prevent stepping through async_hooks.js et al.
+      ]
+    }
+  ]
+}