init: Reworked how we wait for COLDBOOT_DONE

Bug: 31800756

Instead of strictly timing out after 1s waiting for COLDBOOT_DONE,
we wait for a considerably longer period of time, which would also
allow slower non-production heavily instrumented debug builds to
boot up.

Upon successful wait, we measure the time taken and record the
value into a system property: ro.cold_boot.duration.

If timeout is still reached, we log an error message and abandon
boot process, rebooting into recovery mode instead.

Change-Id: Ic1df80546d8721b0e8c998ff294d5c5102de4e98