[hibernate-dev] Make JpaCompliance available earlier

[Steve Ebersole]

I am working on HHH-12282.  I was thinking that the best solution would be
to check this setting at the time when Join#setOptional is called.  The
reason being to centralize the place that this check needs to be done.  I
can do it inside the persister as it consumes the Join, but that leads to
duplicated code.

But in order to fix in the way I just described, we would have to make
JpaCompliance available earlier in the boot process (currently it is built
as part of SessionFactoryOptions/Builder).

WDYT?