process: remove protection for SyncWriteStream destroy in stdio

nodejs#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: nodejs#26691

Author: mcollina

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