fix(test): force process exit after all tests finish

In debug builds, a Node.js-internal referenced async handle keeps the
event loop alive after all tests complete. This is not caused by the
native addon — all addon handles are verified stopped via per-object
create/stop tracking. This does not occur in release builds.

Use tape's onFinish callback to exit with the appropriate code.

Author: kevindhanna

test/all.js

@@ -1,7 +1,14 @@
+/* eslint no-process-exit:0 */
 "use strict";
 
 // require('child_process').spawnSync('pause', {shell: true, stdio: 'inherit'});
 //
+// In debug builds, a Node.js-internal referenced async handle keeps the event
+// loop alive after all tests complete (not caused by the native addon — all
+// addon handles are verified stopped). This does not occur in release builds.
+var test = require("tape");
+test.onFinish(() => process.exit(test._exitCode));
+//
 require("./addicecandidate");
 require("./closing-data-channel");
 require("./closing-peer-connection");