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
```

Backport-PR-URL: #19374
PR-URL: #19177
Refs: #19112
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>

Author: joyeecheung

lib/domain.js

@@ -30,7 +30,7 @@ const util = require('util');
 const EventEmitter = require('events');
 const errors = require('internal/errors');
 const { createHook } = require('async_hooks');
-const { internalBinding } = require('internal/bootstrap_loaders');
+const { internalBinding } = require('internal/bootstrap/loaders');
 
 // overwrite process.domain with a getter/setter that will allow for more
 // effective optimizations

lib/internal/bootstrap_loaders.js renamed to lib/internal/bootstrap/loaders.js

@@ -2,7 +2,7 @@
 // modules. In contrast, user land modules are loaded using
 // lib/module.js (CommonJS Modules) or lib/internal/loader/* (ES Modules).
 //
-// This file is compiled and run by node.cc before bootstrap_node.js
+// This file is compiled and run by node.cc before bootstrap/node.js
 // was called, therefore the loaders are bootstraped before we start to
 // actually bootstrap Node.js. It creates the following objects:
 //
@@ -29,7 +29,7 @@
 //   so they can be loaded faster without the cost of I/O. This class makes the
 //   lib/internal/*, deps/internal/* modules and internalBinding() available by
 //   default to core modules, and lets the core modules require itself via
-//   require('internal/bootstrap_loaders') even when this file is not written in
+//   require('internal/bootstrap/loaders') even when this file is not written in
 //   CommonJS style.
 //
 // Other objects:
@@ -111,7 +111,7 @@
   // Think of this as module.exports in this file even though it is not
   // written in CommonJS style.
   const loaderExports = { internalBinding, NativeModule };
-  const loaderId = 'internal/bootstrap_loaders';
+  const loaderId = 'internal/bootstrap/loaders';
   NativeModule.require = function(id) {
     if (id === loaderId) {
       return loaderExports;
@@ -211,6 +211,6 @@
   };
 
   // This will be passed to the bootstrapNodeJSCore function in
-  // bootstrap_node.js.
+  // bootstrap/node.js.
   return loaderExports;
 });

lib/internal/bootstrap_node.js renamed to lib/internal/bootstrap/node.js

@@ -5,7 +5,7 @@
 // to the performance of the startup process, many dependencies are invoked
 // lazily.
 //
-// Before this file is run, lib/internal/bootstrap_loaders.js gets run first
+// Before this file is run, lib/internal/bootstrap/loaders.js gets run first
 // to bootstrap the internal binding and module loaders, including
 // process.binding(), process._linkedBinding(), internalBinding() and
 // NativeModule. And then { internalBinding, NativeModule } will be passed

lib/internal/loader/CreateDynamicModule.js

@@ -1,6 +1,6 @@
 'use strict';
 
-const { internalBinding } = require('internal/bootstrap_loaders');
+const { internalBinding } = require('internal/bootstrap/loaders');
 const { ModuleWrap } = internalBinding('module_wrap');
 const debug = require('util').debuglog('esm');
 const ArrayJoin = Function.call.bind(Array.prototype.join);

lib/internal/loader/DefaultResolve.js

@@ -3,7 +3,7 @@
 const { URL } = require('url');
 const CJSmodule = require('module');
 const internalFS = require('internal/fs');
-const { NativeModule, internalBinding } = require('internal/bootstrap_loaders');
+const { NativeModule, internalBinding } = require('internal/bootstrap/loaders');
 const { extname } = require('path');
 const { realpathSync } = require('fs');
 const preserveSymlinks = !!process.binding('config').preserveSymlinks;

lib/internal/loader/ModuleJob.js

@@ -1,6 +1,6 @@
 'use strict';
 
-const { internalBinding } = require('internal/bootstrap_loaders');
+const { internalBinding } = require('internal/bootstrap/loaders');
 const { ModuleWrap } = internalBinding('module_wrap');
 const { SafeSet, SafePromise } = require('internal/safe_globals');
 const { decorateErrorStack } = require('internal/util');

lib/internal/loader/ModuleWrap.js

@@ -2,5 +2,5 @@
 
 // exposes ModuleWrap for testing
 
-const { internalBinding } = require('internal/bootstrap_loaders');
+const { internalBinding } = require('internal/bootstrap/loaders');
 module.exports = internalBinding('module_wrap').ModuleWrap;

lib/internal/loader/Translators.js

@@ -1,6 +1,6 @@
 'use strict';
 
-const { NativeModule, internalBinding } = require('internal/bootstrap_loaders');
+const { NativeModule, internalBinding } = require('internal/bootstrap/loaders');
 const { ModuleWrap } = internalBinding('module_wrap');
 const internalCJSModule = require('internal/module');
 const CJSModule = require('module');

lib/internal/process/modules.js

@@ -1,6 +1,6 @@
 'use strict';
 
-const { internalBinding } = require('internal/bootstrap_loaders');
+const { internalBinding } = require('internal/bootstrap/loaders');
 const {
   setImportModuleDynamicallyCallback
 } = internalBinding('module_wrap');

lib/internal/vm/Module.js

@@ -1,6 +1,6 @@
 'use strict';
 
-const { internalBinding } = require('internal/bootstrap_loaders');
+const { internalBinding } = require('internal/bootstrap/loaders');
 const { emitExperimentalWarning } = require('internal/util');
 const { URL } = require('internal/url');
 const { kParsingContext, isContext } = process.binding('contextify');