Migrate libcore benchmarks to BenchmarkRule

This is part of a larger migration effort to move all AndroidX
benchmarks to use BenchmarkRule instead of PerfStatusReporter. It's just the same boring change across all tests.

Change-Id: I309cb9a23102a9ae3680052fa92cd365dacd1443
Merged-In: I309cb9a23102a9ae3680052fa92cd365dacd1443
215 files changed