src: put bootstrappers in lib/internal/bootstrap/

Create `lib/internal/bootstrap/` and put bootstrappers there:

Before:

```
lib/internal
├── ...
├── bootstrap_loaders.js
└── bootstrap_node.js
```

After:

```
lib/internal
├── ...
└── bootstrap
    ├── loaders.js
    └── node.js
```

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>

1 files changed, 3 insertions, 3 deletions

diff --git a/test/parallel/test-loaders-hidden-from-users.js b/test/parallel/test-loaders-hidden-from-users.js
index b3e6622c8c..0d752f5718 100644
--- a/test/parallel/test-loaders-hidden-from-users.js
+++ b/test/parallel/test-loaders-hidden-from-users.js
@@ -6,16 +6,16 @@ const common = require('../common');
 
 common.expectsError(
   () => {
-    require('internal/bootstrap_loaders');
+    require('internal/bootstrap/loaders');
   }, {
     code: 'MODULE_NOT_FOUND',
-    message: 'Cannot find module \'internal/bootstrap_loaders\''
+    message: 'Cannot find module \'internal/bootstrap/loaders\''
   }
 );
 
 common.expectsError(
   () => {
-    const source = 'module.exports = require("internal/bootstrap_loaders")';
+    const source = 'module.exports = require("internal/bootstrap/loaders")';
     process.binding('natives').owo = source;
     require('owo');
   }, {