Experimental fs/promises API is present in the current master without proper test coverage.

According to the coverage report, the following functions are not tested at all:

• fd.chown,
• fd.datasync,
• fd.sync,
• fd.truncate,
• fd.utimes,
• truncate,
• readlink,
• symlink,
• lstat,
• lchmod,
• lchown,
• fchown,
• chown,
• realpath.

#19811 adds a few tests, but that's still not near being complete even after that lands.

Note that tests for lchown should probably be landed after #20407 as that method is currently broken (until #20407 lands).

/cc @mscdex @davisjam @nodejs/testing