lib: restructure cjs and esm loaders

Create `lib/internal/modules` and restructure the module loaders
to make the purpose of those files clearer.

Also make it clear in the code that the object exported by
`lib/internal/modules/cjs/loader.js` is `CJSModule` instead of the
ambiguous `Module`.

Before:

```
lib
├── ...
├── internal
│       ├── loaders
│       │     ├── CreateDynamicModule.js
│       │     ├── DefaultResolve.js
│       │     ├── Loader.js
│       │     ├── ModuleJob.js
│       │     ├── ModuleMap.js
│       │     └── Translators.js
│       └── module.js
└── module.js
```

After:

```
lib
├── ...
├── internal
│       ├── ...
│       └── modules
│              ├── cjs
│              │     ├── helpers.js
│              │     └── loader.js
│              └── esm
│                    ├── CreateDynamicModule.js
│                    ├── DefaultResolve.js
│                    ├── Loader.js
│                    ├── ModuleJob.js
│                    ├── ModuleMap.js
│                    └── Translators.js
└── module.js # deleted in this commit to work with git file mode
```

PR-URL: https://github.com/nodejs/node/pull/19177
Refs: https://github.com/nodejs/node/pull/19112
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>

2 files changed, 5 insertions, 5 deletions

diff --git a/test/es-module/test-esm-loader-modulemap.js b/test/es-module/test-esm-loader-modulemap.js
index 1c1623b680..e9faa6d9f1 100644
--- a/test/es-module/test-esm-loader-modulemap.js
+++ b/test/es-module/test-esm-loader-modulemap.js
@@ -7,10 +7,10 @@
 const common = require('../common');
 
 const { URL } = require('url');
-const Loader = require('internal/loader/Loader');
-const ModuleMap = require('internal/loader/ModuleMap');
-const ModuleJob = require('internal/loader/ModuleJob');
-const createDynamicModule = require('internal/loader/CreateDynamicModule');
+const Loader = require('internal/modules/esm/Loader');
+const ModuleMap = require('internal/modules/esm/ModuleMap');
+const ModuleJob = require('internal/modules/esm/ModuleJob');
+const createDynamicModule = require('internal/modules/esm/CreateDynamicModule');
 
 const stubModuleUrl = new URL('file://tmp/test');
 const stubModule = createDynamicModule(['default'], stubModuleUrl);
diff --git a/test/es-module/test-esm-loader-search.js b/test/es-module/test-esm-loader-search.js
index 4a85ea9325..0f4591a4e3 100644
--- a/test/es-module/test-esm-loader-search.js
+++ b/test/es-module/test-esm-loader-search.js
@@ -5,7 +5,7 @@
 
 const common = require('../common');
 
-const { search } = require('internal/loader/DefaultResolve');
+const { search } = require('internal/modules/esm/DefaultResolve');
 
 common.expectsError(
   () => search('target', undefined),