fetch: use EOL of os-module (#2915)

lib/web/fetch/file.js

@@ -1,12 +1,14 @@
 'use strict'
 
+const { EOL } = require('node:os')
 const { Blob, File: NativeFile } = require('node:buffer')
 const { types } = require('node:util')
 const { kState } = require('./symbols')
 const { isBlobLike } = require('./util')
 const { webidl } = require('./webidl')
 const { parseMIMEType, serializeAMimeType } = require('./data-url')
 const { kEnumerableProperty } = require('../../core/util')
+
 const encoder = new TextEncoder()
 
 class File extends Blob {
@@ -307,17 +309,14 @@ function processBlobParts (parts, options) {
  */
 function convertLineEndingsNative (s) {
   // 1. Let native line ending be be the code point U+000A LF.
-  let nativeLineEnding = '\n'
-
   // 2. If the underlying platform’s conventions are to
   //    represent newlines as a carriage return and line feed
   //    sequence, set native line ending to the code point
   //    U+000D CR followed by the code point U+000A LF.
-  if (process.platform === 'win32') {
-    nativeLineEnding = '\r\n'
-  }
+  // NOTE: We are using the native line ending for the current
+  // platform, provided by node's os module.
 
-  return s.replace(/\r?\n/g, nativeLineEnding)
+  return s.replace(/\r?\n/g, EOL)
 }
 
 // If this function is moved to ./util.js, some tools (such as