Improve CPU ABI naming in the benchmark

[pzread]

Currently we have __get_arm_cpu_arch_revision in the benchmark tool to derive the subversion of ARM processor, such as ARMv8.2-A. Our method to derive it is not complete, and we might just want to have ARMv8-A. However, there are also ARMv9 processors reporting ARMv8-A as CPU ABI, and we still want to differentiate them.

Changing the naming will also invalid the existing records in perf dashboard, we need a backfill to fix them.

[antiagainst]

Thanks for capturing this! Yeah it'll need to rewrite existing benchmark names, which we have done once previously. I can do it again.

For armv9 devices (like moto edge x30 we have right now), we might need to look at more information from adb shell getprop to differentiate.