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, 1 insertions, 1 deletions

diff --git a/lib/buffer.js b/lib/buffer.js
index 7703d2a129..b369d27a1e 100644
--- a/lib/buffer.js
+++ b/lib/buffer.js
@@ -41,7 +41,7 @@ const {
 // that test/parallel/test-buffer-bindingobj-no-zerofill.js is written.
 let isAnyArrayBuffer;
 try {
-  const { internalBinding } = require('internal/bootstrap_loaders');
+  const { internalBinding } = require('internal/bootstrap/loaders');
   isAnyArrayBuffer = internalBinding('types').isAnyArrayBuffer;
 } catch (e) {
   isAnyArrayBuffer = require('util').types.isAnyArrayBuffer;