test: use random port in test-inspector-enabled

Which makes it possible to run it in parallel.

PR-URL: nodejs#47412
Refs: nodejs#47146
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

test/sequential/test-inspector-enabled.js

@@ -19,7 +19,7 @@ assert(
   'inspector.isEnabled() should be false after _debugEnd()');
 `;
 
-const args = ['--inspect', '-e', script];
+const args = ['--inspect=0', '-e', script];
 const child = spawn(process.execPath, args, {
   stdio: 'inherit',
   env: { ...process.env, NODE_V8_COVERAGE: '' }