[Ravenwood] "Fake" ravenizer script

This is needed to merge the soong change in AOSP without not having
the actual ravenizer tool.

Test: manual -- run `m RavenwoodBivalentTest` and make sure the ravenizer
    log message shows up.
Flag: EXEMPT host test change only
Bug: 360390999
Change-Id: Idf34f93846ce35ec6666ad0a63ab2bf5408ba8cb