[ Merge of http://go/wvgerrit/115548 ]
Create a small set of unittests to verify the functionality of OEM
Certificate.
This adds a test OEM Public Certificate and OEM Private Key.
Bug: 135283522
Test: oemcrypto_unittests
Change-Id: Iaa634543d9cb5005d91f1e7c528bf05b2b0c4d68