Redshift name type

[hsheth2]

Reopening #3107

I filed the bug against the postgres dialect, but was actually using Redshift myself. It seems this bug only appears for Redshift, despite the redshift dialect being based on postgres.

from sqlglot import parse_one

parse_one("""
SELECT pgc.relname::CHARACTER varying AS textin
  FROM pg_class pgc
 WHERE pgc.relname <> 'my_table'::name
 """, read="redshift")