test: refactor beforeExit tests

Combine and rename tests for the `beforeExit` event on `process`.

The naming now more closely follows the de facto conventions of the
project.

The two tests were very similar and do not seem to benefit from being
separate.

PR-URL: nodejs#10581
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>

test/parallel/test-beforeexit-event.js → test/parallel/test-process-beforeexit.js

@@ -21,6 +21,19 @@ function tryListen() {
     .listen(0)
     .on('listening', common.mustCall(function() {
       this.close();
-      process.on('beforeExit', common.mustCall(() => {}));
+      process.once('beforeExit', common.mustCall(tryRepeatedTimer));
     }));
 }
+
+// test that a function invoked from the beforeExit handler can use a timer
+// to keep the event loop open, which can use another timer to keep the event
+// loop open, etc.
+function tryRepeatedTimer() {
+  const N = 5;
+  let n = 0;
+  const repeatedTimer = common.mustCall(function() {
+    if (++n < N)
+      setTimeout(repeatedTimer, 1);
+  }, N);
+  setTimeout(repeatedTimer, 1);
+}