pgsql: Fix markTargetListOrigin() to not fail on a simple-Var reference

Log Message:
-----------
Fix markTargetListOrigin() to not fail on a simple-Var reference to a
recursive CTE that we're still in progress of analyzing.  Add a similar guard
to the similar code in expandRecordVariable(), and tweak regression tests to
cover this case.  Per report from Dickson S. Guedes.

Modified Files:
--------------
    pgsql/src/backend/parser:
        parse_target.c (r1.165 -> r1.166)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/parse_target.c?r1=1.165&r2=1.166)
    pgsql/src/test/regress/expected:
        with.out (r1.1 -> r1.2)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/with.out?r1=1.1&r2=1.2)
    pgsql/src/test/regress/sql:
        with.sql (r1.1 -> r1.2)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/sql/with.sql?r1=1.1&r2=1.2)