test: make test-os-checked-function work without test harness

Most tests in `test/parallel` work when invoked with `node` rather than
`tools/test.py` but not test-os-checked-function because it doesn't load
the `common` module initially, which means it won't get re-spawned with
the necessary flags (in the Flags: comment, in this case
--expose_internals). Now that common delays loading 'os' until it needs
to load it, this test can load the common module and it will work from
the command line without the test harness. Additionally, we now can
remove a comment disabling a lint rule.

test/parallel/test-os-checked-function.js

@@ -1,7 +1,7 @@
-/* eslint-disable node-core/require-common-first */
 'use strict';
 // Flags: --expose_internals
 
+const common = require('../common');
 const { internalBinding } = require('internal/test/binding');
 
 // Monkey patch the os binding before requiring any other modules, including
@@ -12,7 +12,6 @@ internalBinding('os').getHomeDirectory = function(ctx) {
   ctx.message = 'baz';
 };
 
-const common = require('../common');
 const os = require('os');
 
 common.expectsError(os.homedir, {