process: make Symbol.toStringTag writable

The ecosystem broke by making it non-writable, so this is a good
intermediate fix.

PR-URL: https://github.com/nodejs/node/pull/26488
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Yuta Hiroto <hello@hiroppy.me>
Reviewed-By: James M Snell <jasnell@gmail.com>

lib/internal/bootstrap/node.js

@@ -283,7 +283,7 @@ function setupProcessObject() {
   EventEmitter.call(process);
   Object.defineProperty(process, Symbol.toStringTag, {
     enumerable: false,
-    writable: false,
+    writable: true,
     configurable: false,
     value: 'process'
   });

test/es-module/test-esm-process.mjs

@@ -4,3 +4,4 @@ import assert from 'assert';
 import process from 'process';
 
 assert.strictEqual(Object.prototype.toString.call(process), '[object process]');
+assert(Object.getOwnPropertyDescriptor(process, Symbol.toStringTag).writable);