util: inspect __proto__ key as written in object literal

Since util.inspect() gives object-literal-like output, handle the
special `__proto__` key in the way that it would be handled in object
literals.

PR-URL: #37713
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: Gerhard Stöbich <deb2001-github@yahoo.de>

lib/internal/util/inspect.js

@@ -1718,6 +1718,8 @@ function formatProperty(ctx, value, recurseTimes, key, type, desc,
       strEscapeSequencesReplacer, escapeFn
     );
     name = `[${ctx.stylize(tmp, 'symbol')}]`;
+  } else if (key === '__proto__') {
+    name = "['__proto__']";
   } else if (desc.enumerable === false) {
     const tmp = StringPrototypeReplace(key,
                                        strEscapeSequencesReplacer, escapeFn);

test/parallel/test-util-inspect.js

@@ -3095,3 +3095,10 @@ assert.strictEqual(
     ']'
   );
 }
+
+{
+  assert.strictEqual(
+    util.inspect({ ['__proto__']: { a: 1 } }),
+    "{ ['__proto__']: { a: 1 } }"
+  );
+}