apply render_schema_translates to identity insert directives

apply render_schema_translates to identity insert directives

Fixed bug where the "schema_translate_map" feature would fail to function
correctly in conjunction with an INSERT into a table that has an IDENTITY
column, where the value of the IDENTITY column were specified in the values
of the INSERT thus triggering SQLAlchemy's feature of setting IDENTITY
INSERT to "on"; it's in this directive where the schema translate map would
fail to be honored.

Fixes: #6658
Change-Id: I8235aa639dd465d038a2ad48e7a669f3e5c5c37c