test_runner: fix it concurrency

PR-URL: #43757
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Jacob Smith <jacob@frende.me>

lib/internal/test_runner/test.js

@@ -1,15 +1,14 @@
 'use strict';
 const {
   ArrayPrototypePush,
-  ArrayPrototypeReduce,
   ArrayPrototypeShift,
   ArrayPrototypeUnshift,
   FunctionPrototype,
   Number,
-  PromiseResolve,
   ReflectApply,
   SafeMap,
   PromiseRace,
+  SafePromiseAll,
 } = primordials;
 const { AsyncResource } = require('async_hooks');
 const {
@@ -506,10 +505,7 @@ class Suite extends Test {
     this.parent.activeSubtests++;
     this.startTime = hrtime();
     const subtests = this.skipped || this.error ? [] : this.subtests;
-    await testTimeout(ArrayPrototypeReduce(subtests, async (prev, subtest) => {
-      await prev;
-      await subtest.run();
-    }, PromiseResolve()), this.timeout);
+    await SafePromiseAll(subtests, (subtests) => subtests.start());
     this.pass();
     this.postRun();
   }

test/message/test_runner_describe_it.out

@@ -188,6 +188,10 @@ ok 20 - immediate resolve pass
         *
         *
         *
+        *
+        *
+        *
+        *
       ...
     1..1
 not ok 21 - subtest sync throw fail
@@ -471,6 +475,9 @@ not ok 53 - custom inspect symbol that throws fail
         *
         *
         *
+        *
+        *
+        *
       ...
     # Subtest: sync throw fails at second
     not ok 2 - sync throw fails at second
@@ -486,6 +493,10 @@ not ok 53 - custom inspect symbol that throws fail
         *
         *
         *
+        *
+        *
+        *
+        *
       ...
     1..2
 not ok 54 - subtest sync throw fails
@@ -559,6 +570,8 @@ not ok 56 - describe async throw fails
       failureType: 'testTimeoutFailure'
       error: 'test timed out after 5ms'
       code: 'ERR_TEST_FAILURE'
+      stack: |-
+        *
       ...
     # Subtest: timed out callback test
     not ok 2 - timed out callback test