chore: use internal namespace in 40_testing.js (#21141)

Towards #21136 

- [x] assign serializePermissions, setTimeout and setExitHandler APIs to
internal namespace
- [x] remove usage of assert

1 files changed, 3 insertions, 0 deletions

diff --git a/runtime/js/30_os.js b/runtime/js/30_os.js
index a5a55e19b..583449083 100644
--- a/runtime/js/30_os.js
+++ b/runtime/js/30_os.js
@@ -2,6 +2,7 @@
 
 const core = globalThis.Deno.core;
 const ops = core.ops;
+const internals = globalThis.__bootstrap.internals;
 import { Event, EventTarget } from "ext:deno_web/02_event.js";
 const primordials = globalThis.__bootstrap.primordials;
 const {
@@ -106,6 +107,8 @@ function execPath() {
   return ops.op_exec_path();
 }
 
+internals.setExitHandler = setExitHandler;
+
 export {
   env,
   execPath,