Move processNamePattern into dumputils.c in preparation for using it in

Move processNamePattern into dumputils.c in preparation for using it in
pg_dump as well as psql.  Since psql already uses dumputils.c, while there's
not any code sharing in the other direction, this seems the easiest way.
Also, fix misinterpretation of patterns using regex | by adding parentheses
(same bug found previously in similar_escape()).  This should be backpatched.