add timestamps to logged messages

Having basic timestamps for logged messages can help narrow down
issues in builds.  We already do this for Python code, so add it
to our shell scripts too.  Some of the steps here can take quite
a long time to run.

BUG=None
TEST=sdk bootstrap & CQ passes

Change-Id: I6dd1e352f898d8213ec92574097bbe4c040ef613
Reviewed-on: https://chromium-review.googlesource.com/1789856
Tested-by: Mike Frysinger <vapier@chromium.org>
Commit-Ready: Mike Frysinger <vapier@chromium.org>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Alex Klein <saklein@chromium.org>
2 files changed