pgsql: Remove duplicated code left behind by my recent refactoring of

Log Message:
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Remove duplicated code left behind by my recent refactoring of comment.c

These checks are also present in objectaddress.c, so there's no need to
recheck here.

Modified Files:
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    pgsql/src/backend/commands:
        comment.c (r1.118 -> r1.119)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/comment.c?r1=1.118&r2=1.119)