test: update error message keywords

This testcase failed on Apple Silicon M1, add the error message pattern:
`not a mach-o file`

PR-URL: #39826
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Khaidi Chu <i@2333.moe>

test/parallel/test-module-loading-error.js

@@ -28,7 +28,7 @@ const errorMessagesByPlatform = {
   win32: ['is not a valid Win32 application'],
   linux: ['file too short', 'Exec format error'],
   sunos: ['unknown file type', 'not an ELF file'],
-  darwin: ['file too short'],
+  darwin: ['file too short', 'not a mach-o file'],
   aix: ['Cannot load module',
         'Cannot run a file that does not have a valid format.',
         'Exec format error'],