fs: check for symlink support in fs-promises test

Attempting to make symlinks as a non-administrator user in Windows
causes a permission error. We need to update test-fs-promises to avoid
making symlinks if the platform does not support it.

PR-URL: #19018
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Shingo Inoue <leko.noor@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Author: sethbrenith

test/parallel/test-fs-promises.js

@@ -116,21 +116,24 @@ function verifyStatObject(stat) {
     stats = await stat(newPath);
     verifyStatObject(stats);
 
-    const newLink = path.resolve(tmpDir, 'baz3.js');
-    await symlink(newPath, newLink);
+    if (common.canCreateSymLink()) {
+      const newLink = path.resolve(tmpDir, 'baz3.js');
+      await symlink(newPath, newLink);
 
-    const newLink2 = path.resolve(tmpDir, 'baz4.js');
-    await link(newPath, newLink2);
+      stats = await lstat(newLink);
+      verifyStatObject(stats);
 
-    stats = await lstat(newLink);
-    verifyStatObject(stats);
+      assert.strictEqual(newPath.toLowerCase(),
+                         (await realpath(newLink)).toLowerCase());
+      assert.strictEqual(newPath.toLowerCase(),
+                         (await readlink(newLink)).toLowerCase());
 
-    assert.strictEqual(newPath.toLowerCase(),
-                       (await realpath(newLink)).toLowerCase());
-    assert.strictEqual(newPath.toLowerCase(),
-                       (await readlink(newLink)).toLowerCase());
+      await unlink(newLink);
+    }
+
+    const newLink2 = path.resolve(tmpDir, 'baz4.js');
+    await link(newPath, newLink2);
 
-    await unlink(newLink);
     await unlink(newLink2);
 
     const newdir = path.resolve(tmpDir, 'dir');