Merge "Improve fchmod() coverage." am: 4b6a29dbe9 am: a49b30f03c

Original change: https://android-review.googlesource.com/c/platform/bionic/+/1623242

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I95a5a96679501ce64e49fa6bd7696276836ad221