repair schema_translate_map for schema type use cases

repair schema_translate_map for schema type use cases

Fixed issue where the PostgreSQL ``ENUM`` datatype as embedded in the
``ARRAY`` datatype would fail to emit correctly in create/drop when the
``schema_translate_map`` feature were also in use. Additionally repairs a
related issue where the same ``schema_translate_map`` feature would not
work for the ``ENUM`` datatype in combination with a ``CAST``, that's also
intrinsic to how the ``ARRAY(ENUM)`` combination works on the PostgreSQL
dialect.

Fixes: #6739
Change-Id: I44b1ad4db4af3acbf639aa422c46c22dd3b0d3a6