Fix timeout when running device policy CTS

Run all CTS using common libraries rather than calling am instrumentation
directly, to prevent timeouts. Timeout is set to two minutes by default
for regular adb commands, while there is no timeout if calling through
libraries. Managed profile tests something take over 2m as they have to
create and remove a user

Bug: 27358435
Change-Id: I42b0304f20f996684574c1e329b5ef8d179aed15
7 files changed