Upgrade kotlinx.atomicfu to 0.18.5 am: b943793454 am: 2282b1ddcd am: 2fe11a0356

Original change: https://android-review.googlesource.com/c/platform/external/kotlinx.atomicfu/+/2281219

Change-Id: I9e9ec7b3e99d3b2f34dce2cecbe274987311a09f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>