qualify compile_state updates for non-current entities

qualify compile_state updates for non-current entities

Fixed issue in recently repaired ``Query.with_entities()`` method where the
flag that determines automatic uniquing for legacy ORM ``Query`` objects
only would be set to ``True`` inappropriately in cases where the
``with_entities()`` call would be setting the ``Query`` to return
column-only rows, which are not uniqued.

Fixes: #6924
Change-Id: I81120823914c989bb7a4d13ef2ec08809d8e5a4d