[FIX] orm: access error due to prefetch of indirectly referenced records.

The new-api record prefetching algorithm attempts
to load data for all known records from the requested
model (i.e. all IDs present in the environment cache),
regardless of how indirectly/remotely they were
referenced. An indirect parent record may therefore
be prefetched along with its directly browsed children,
possibly crossing company boundaries involuntarily.

This patch implements a fallback mechanism when
the prefetching failed due to what looks like an
ACL restriction.

The implementation of `_read_from_database` handle
ACL directly and set an `AccessError` as cache value
for restricted records.

If a model (like `mail.message`) overwrites `read` to
implements its own ACL checks and raises an `AccessError`
before calling `super()` (which will then call
`_read_from_database`), the cache will be not fill,
leading to an unexpected exception.

If this commit messae looks familiar to you, that's
simply because this is the new-api counterpart of
b7865502