lib: remove deprecated 'sys'

this appears to have been deprecated since node 0.7. perhaps it’s time to remove it?

Author: ljharb

lib/sys.js

@@ -87,7 +87,6 @@
       'lib/_stream_passthrough.js',
       'lib/_stream_wrap.js',
       'lib/string_decoder.js',
-      'lib/sys.js',
       'lib/timers/promises.js',
       'lib/timers.js',
       'lib/tls.js',

node.gyp

@@ -1,5 +1,5 @@
 'use strict';
-require('sys');  // Builtin should not show up in module.children array.
+require('util');  // Builtin should not show up in module.children array.
 require('./b');  // This should.
 require('./b');  // This should not.
 module.exports = module.children.slice();

test/fixtures/GH-7131/a.js

@@ -60,7 +60,6 @@ const expectedPublicModules = new Set([
   'repl',
   'stream',
   'string_decoder',
-  'sys',
   'timers',
   'tls',
   'trace_events',

test/parallel/test-internal-module-require.js

@@ -5,7 +5,7 @@ const { builtinModules } = require('module');
 
 // Includes modules in lib/ (even deprecated ones)
 assert(builtinModules.includes('http'));
-assert(builtinModules.includes('sys'));
+assert(builtinModules.includes('util'));
 
 // Does not include internal modules
 assert.deepStrictEqual(