Merge "libc: swap memrchr to llvm-libc for most arches" into main am: c20dad55e8 am: aac8cbac2f

Original change: https://android-review.googlesource.com/c/platform/bionic/+/3368659

Change-Id: Ie87ea83789a47dd1d364b85ba38b3143bbb28c40
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>