Upgrade google-benchmark to v1.8.4 am: 4643d20873

Original change: https://android-review.googlesource.com/c/platform/external/google-benchmark/+/3118328

Change-Id: I12b0128c0ff1335fee5308c22de3bc72bde4b0d7
Signed-off-by: Automerger Merge Worker <[email protected]>