test: deflake child-process-pipe-dataflow

Fixes: #25988

test/parallel/test-child-process-pipe-dataflow.js

@@ -3,7 +3,6 @@ const common = require('../common');
 const assert = require('assert');
 const path = require('path');
 const fs = require('fs');
-const os = require('os');
 const spawn = require('child_process').spawn;
 const tmpdir = require('../common/tmpdir');
 
@@ -27,7 +26,7 @@ const MB = KB * KB;
   // So cut the buffer into lines at some points, forcing
   // data flow to be split in the stream.
   for (let i = 1; i < KB; i++)
-    buf.write(os.EOL, i * KB);
+    buf.write('\n', i * KB);
   fs.writeFileSync(file, buf.toString());
 
   cat = spawn('cat', [file]);