process: remove protection for SyncWriteStream destroy in stdio

#26691 introduced an if to protect
against SyncWriteStream not using the default .destroy() mechanism.
This change removes that as SyncWriteStream now use standard .destroy().

See: #26691

PR-URL: #26902
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

lib/internal/process/stdio.js

@@ -3,13 +3,7 @@
 exports.getMainThreadStdio = getMainThreadStdio;
 
 function dummyDestroy(err, cb) {
-  // SyncWriteStream does not use the stream
-  // destroy mechanism for some legacy reason.
-  // TODO(mcollina): remove when
-  // https://github.com/nodejs/node/pull/26690 lands.
-  if (typeof cb === 'function') {
-    cb(err);
-  }
+  cb(err);
 
   // We need to emit 'close' anyway so that the closing
   // of the stream is observable. We just make sure we