Add additional variables to ninja variable whitelist

These variables control whether we accept cached-results / not and
whether we should update the cache with locally executed results or not.
I need accpet-cached whitelisted to purge the the RBE cache for the
invalid cache entry we have set for the failure we say yesterday.

Bug: b/148387048

Change-Id: I7344fc083f82e0b7bc11084376a267d19cf30bb8