Merge "Enable coverage for libc." am: e41012fe2e am: fab04f7527 am: 3fcc2f13f1 am: 6f915ad2c6

Original change: https://android-review.googlesource.com/c/platform/bionic/+/1383511

Change-Id: Iceb84105b1f1687165f18f0b80c50b3f4cd05a02