Include schema in all_tab_comments query

Include schema in all_tab_comments query

Fixed regression / incorrect fix caused by fix for :ticket:`5146` where the
Oracle dialect reads from the "all_tab_comments" view to get table comments
but fails to accommodate for the current owner of the table being
requested, causing it to read the wrong comment if multiple tables of the
same name exist in multiple schemas.

Fixes: #5146
Change-Id: Id79fbaa81b0e36cd4af60c48e4ab35c593ace057
(cherry picked from commit f1429823d31c56b589017e60328f826f5e721f0e)