pgsql-server: Further tightening of the array literal parser.

Log Message:
-----------
Further tightening of the array literal parser. Prevent junk
from being accepted after the outer right brace. Per report from
Markus Bertheau.

Also add regression test cases for this change, and for previous
recent array literal parser changes.

Modified Files:
--------------
    pgsql-server/src/backend/utils/adt:
        arrayfuncs.c (r1.107 -> r1.108)

(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/utils/adt/arrayfuncs.c.diff?r1=1.107&r2=1.108)
    pgsql-server/src/test/regress/expected:
        arrays.out (r1.22 -> r1.23)

(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/test/regress/expected/arrays.out.diff?r1=1.22&r2=1.23)
    pgsql-server/src/test/regress/sql:
        arrays.sql (r1.17 -> r1.18)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/test/regress/sql/arrays.sql.diff?r1=1.17&r2=1.18)