set up is_from_statement and others for FromStatement

set up is_from_statement and others for FromStatement

Added new attribute :attr:`_orm.ORMExecuteState.is_from_statement`, to
detect statements of the form ``select().from_statement()``, and also
enhanced ``FromStatement`` to set :attr:`_orm.ORMExecuteState.is_select`,
:attr:`_orm.ORMExecuteState.is_insert`,
:attr:`_orm.ORMExecuteState.is_update`, and
:attr:`_orm.ORMExecuteState.is_delete` according to the element that is
sent to the :meth:`_sql.Select.from_statement` method itself.

Fixes: #11220
Change-Id: I3bf9e7e22fa2955d772b3b6ad636ed93a60916ae