Revert "bootstat: Refactor init/utils/boot_clock into base/chrono_utils."

This reverts commit 7c92e484503f239000ef97ef5b067907fbeaa4a6.

Mac sdk still broken (despite testing locally).

Change-Id: I7d9206e15997cd0efe081bd3fa17d53d2b20ec32
16 files changed