Move edge time from Status to Builder

The times that end up in the build log currently originate in the
status printer, and are propagated back out to the Builder.  Move
the edge times into the Builder instead, and move the overall start
time into NinjaMain so it doesn't get reset during manifest
rebuilds.

(cherry-picked from commit 12c68775537aa76f3b81676d10b290c4074df531)

Change-Id: I710268cb5e95277fc82c37f6963864aa9e13353e
4 files changed