Since the module has to be loaded during bootstrap anyway.

The helpers are actually shared by the two loaders, so move them
under modules/ directly.

This patch adds a getLazy() method to facilitate initialize-once
lazy loading in the internals.

So that the file can be snapshotted.

So that the file can be snapshotted

This moves the following utils into modules/esm/utils.js:

- Code related to default conditions
- The callbackMap (which is now created in the module instead of
  hanging off the module_wrap binding, since the C++ land
  does not need it).
- Per-isolate module callbacks

These are self-contained code that can be included into the
built-in snapshot.

This patch makes the top-level access to runtime states in the
CJS loader lazy, and move the side-effects into a
initializeCJS() function that gets called during pre-execution.
As a result the CJS loader can be included into the built-in
snapshot.

Preload essential modules and lazy-load non-essential ones.
After this patch, all modules listed by running this snippet:

```
const list = process.moduleLoadList.join('\n');
require('fs').writeSync(1, list, 'utf-8');
```

(which is roughly the same list as the one in
test-bootstrap-module.js for the main thread)
are loaded from the snapshot so no additional compilation cost
is incurred.