Merge from Widevine repo of http://go/wvgerrit/43720
This CL changes the cdm engine test's Provision method so that it
keeps OEMCrypto alive during the provisioning. This is only needed
when testing with the oemcrypto mock and the nonce flood rate has been
throttled to 1. In that case, if OEMCrypto is allowed to terminate
between each request, all nonce requests will be an error.
Keeping OEMCrypto alive does not modify the desired test results when
oemcrypto is not throttled.
This CL changes test code only.
bug: 73607610
test: unit tests
Change-Id: I71b27b1bb8200188a0a821afc977d7a9cc7fd968