Revert "Migrate libcore benchmarks to BenchmarkRule"

This reverts commit e292bf87b548929d4c3fc7740b653962f345239f.

Reason for revert: This has been causing failures and is not does not seem compatible with the CB dashboard

Change-Id: Iea68da6aae4d5cc4f72b65268e522e22e34b45fe
215 files changed