stream: remove dead code

`String.prototype.split()` returns an array of strings so the branch is
never taken.

Fixes: nodejs#30040

PR-URL: nodejs#30041
Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>
Reviewed-By: David Carlier <devnexen@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Jiawen Geng <technicalcute@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>

lib/stream.js

@@ -43,23 +43,18 @@ Stream.Stream = Stream;
 
 Stream._isUint8Array = require('internal/util/types').isUint8Array;
 
-const version = process.version.substr(1).split('.');
-if (version[0] === 0 && version[1] < 12) {
-  Stream._uint8ArrayToBuffer = Buffer;
-} else {
-  try {
-    const internalBuffer = require('internal/buffer');
-    Stream._uint8ArrayToBuffer = function _uint8ArrayToBuffer(chunk) {
-      return new internalBuffer.FastBuffer(chunk.buffer,
-                                           chunk.byteOffset,
-                                           chunk.byteLength);
-    };
-  } catch (e) { // eslint-disable-line no-unused-vars
-  }
+try {
+  const internalBuffer = require('internal/buffer');
+  Stream._uint8ArrayToBuffer = function _uint8ArrayToBuffer(chunk) {
+    return new internalBuffer.FastBuffer(chunk.buffer,
+                                         chunk.byteOffset,
+                                         chunk.byteLength);
+  };
+} catch (e) { // eslint-disable-line no-unused-vars
+}
 
-  if (!Stream._uint8ArrayToBuffer) {
-    Stream._uint8ArrayToBuffer = function _uint8ArrayToBuffer(chunk) {
-      return Buffer.prototype.slice.call(chunk);
-    };
-  }
+if (!Stream._uint8ArrayToBuffer) {
+  Stream._uint8ArrayToBuffer = function _uint8ArrayToBuffer(chunk) {
+    return Buffer.prototype.slice.call(chunk);
+  };
 }