Do initialization early.

Do initialization early.

Previously, FESystem delayed initializing the base element's data
objects until we first visited fill_fe_values(). Do this earlier:
when the base element's data objects are first created.

This involves a change in the update flags being used. I think that
there is some confusion about update flags anyway, since we should
always be using update_each. The change made here passes the testsuite,
so I believe it is correct. It is likely also easier to understand
than what the old code did.