test: add test for fs.lchmod

Test passed on macOS:

$ uname                                                                                                                           
Darwin
$ python tools/test.py -J --mode=release parallel/test-fs-lchmod 
[00:00|% 100|+   1|-   0]: Done

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• commit message follows commit guidelines