cryptohome: Fixed and re-enabled Service unit tests.

Cleaned up the service unit tests with reliable mock destruction order
and other fixes.

Also made cryptohome unit tests run >300x faster, which is nice.

BUG=chromium:451192
TEST=unit, manual sanity test

Change-Id: I5ef6102bd52713568768ecef6e6762925a19859f
Reviewed-on: https://chromium-review.googlesource.com/272266
Reviewed-by: Utkarsh Sanghi <usanghi@chromium.org>
Commit-Queue: Darren Krahn <dkrahn@chromium.org>
Tested-by: Darren Krahn <dkrahn@chromium.org>
2 files changed