test: use fixtures.fileURL when appropriate

PR-URL: nodejs/node#48990
Backport-PR-URL: nodejs/node#50669
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Chemi Atlow <chemi@atlow.co.il>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

graal-nodejs/test/parallel/test-fs-whatwg-url.js

@@ -3,20 +3,10 @@
 const common = require('../common');
 const fixtures = require('../common/fixtures');
 const assert = require('assert');
-const path = require('path');
 const fs = require('fs');
 const os = require('os');
 
-function pathToFileURL(p) {
-  if (!path.isAbsolute(p))
-    throw new Error('Path must be absolute');
-  if (common.isWindows && p.startsWith('\\\\'))
-    p = p.slice(2);
-  return new URL(`file://${p}`);
-}
-
-const p = path.resolve(fixtures.fixturesDir, 'a.js');
-const url = pathToFileURL(p);
+const url = fixtures.fileURL('a.js');
 
 assert(url instanceof URL);
 

graal-nodejs/test/parallel/test-module-create-require.js

@@ -1,13 +1,12 @@
 'use strict';
 
 require('../common');
+const fixtures = require('../common/fixtures');
 const assert = require('assert');
-const path = require('path');
 
 const { createRequire } = require('module');
 
-const p = path.resolve(__dirname, '..', 'fixtures', 'fake.js');
-const u = new URL(`file://${p}`);
+const u = fixtures.fileURL('fake.js');
 
 const reqToo = createRequire(u);
 assert.deepStrictEqual(reqToo('./experimental'), { ofLife: 42 });