test: improve check in test-os

The check for `os.networkInterfaces()` in `test-os.js` may be too
strict. It's apparently possible for a machine to be configured with
multiple IPv4 loopback interfaces. Increase specificity of filter to
check on only the object we expect.

PR-URL: #14655
Fixes: #14654
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: Trott

test/parallel/test-os.js

@@ -116,7 +116,8 @@ const interfaces = os.networkInterfaces();
 switch (platform) {
   case 'linux':
   {
-    const filter = (e) => e.address === '127.0.0.1';
+    const filter =
+      (e) => e.address === '127.0.0.1' && e.netmask === '255.0.0.0';
     const actual = interfaces.lo.filter(filter);
     const expected = [{ address: '127.0.0.1', netmask: '255.0.0.0',
                         mac: '00:00:00:00:00:00', family: 'IPv4',