Merge from Widevine repo of http://go/wvgerrit/56522
This CL moves provisioning from core/test/cdm_engine_test.cpp to
test_base.cpp because other tests should also only be run when the
device has been provisioned.
It also adds a fake license server. The license holder helps a test
create a license request and then generates a bare-bones license,
without actually sending anything to a real license server.
Test: more unit tests pass than before.
Bug: 72354901 Fix Generic Crypto tests.
Change-Id: Iec067a6a1fb91fa8fd7b904fdf36e90981e293a3
790799ceaa