pgsql: Fix up the remaining places where the expression node structure

Log Message:
-----------
Fix up the remaining places where the expression node structure would lose
available information about the typmod of an expression; namely, Const,
ArrayRef, ArrayExpr, and EXPR and ARRAY SubLinks.  In the ArrayExpr and
SubLink cases it wasn't really the data structure's fault, but exprTypmod()
being lazy.  This seems like a good idea in view of the expected increase in
typmod usage from Teodor's work to allow user-defined types to have typmods.
In particular this responds to the concerns we had about eliminating the
special-purpose hack that exprTypmod() used to have for BPCHAR Consts.
We can now tell whether or not such a Const has been cast to a specific
length, and report or display properly if so.

initdb forced due to changes in stored rules.

Modified Files:
--------------
    pgsql/src/backend/nodes:
        copyfuncs.c (r1.370 -> r1.371)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/copyfuncs.c.diff?r1=1.370&r2=1.371)
        equalfuncs.c (r1.301 -> r1.302)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/equalfuncs.c.diff?r1=1.301&r2=1.302)
        makefuncs.c (r1.54 -> r1.55)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/makefuncs.c.diff?r1=1.54&r2=1.55)
        outfuncs.c (r1.303 -> r1.304)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/outfuncs.c.diff?r1=1.303&r2=1.304)
        readfuncs.c (r1.203 -> r1.204)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/readfuncs.c.diff?r1=1.203&r2=1.204)
    pgsql/src/backend/optimizer/path:
        indxpath.c (r1.216 -> r1.217)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/path/indxpath.c.diff?r1=1.216&r2=1.217)
    pgsql/src/backend/optimizer/plan:
        planagg.c (r1.29 -> r1.30)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/plan/planagg.c.diff?r1=1.29&r2=1.30)
    pgsql/src/backend/optimizer/prep:
        preptlist.c (r1.86 -> r1.87)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/prep/preptlist.c.diff?r1=1.86&r2=1.87)
        prepunion.c (r1.139 -> r1.140)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/prep/prepunion.c.diff?r1=1.139&r2=1.140)
    pgsql/src/backend/optimizer/util:
        clauses.c (r1.238 -> r1.239)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/util/clauses.c.diff?r1=1.238&r2=1.239)
        predtest.c (r1.13 -> r1.14)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/util/predtest.c.diff?r1=1.13&r2=1.14)
    pgsql/src/backend/parser:
        parse_coerce.c (r2.150 -> r2.151)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/parse_coerce.c.diff?r1=2.150&r2=2.151)
        parse_expr.c (r1.212 -> r1.213)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/parse_expr.c.diff?r1=1.212&r2=1.213)
        parse_node.c (r1.96 -> r1.97)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/parse_node.c.diff?r1=1.96&r2=1.97)
    pgsql/src/backend/rewrite:
        rewriteHandler.c (r1.171 -> r1.172)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/rewrite/rewriteHandler.c.diff?r1=1.171&r2=1.172)
    pgsql/src/backend/utils/adt:
        ruleutils.c (r1.253 -> r1.254)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/ruleutils.c.diff?r1=1.253&r2=1.254)
        selfuncs.c (r1.228 -> r1.229)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/selfuncs.c.diff?r1=1.228&r2=1.229)
    pgsql/src/backend/utils/cache:
        lsyscache.c (r1.148 -> r1.149)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/cache/lsyscache.c.diff?r1=1.148&r2=1.149)
    pgsql/src/include/catalog:
        catversion.h (r1.390 -> r1.391)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/catversion.h.diff?r1=1.390&r2=1.391)
    pgsql/src/include/nodes:
        makefuncs.h (r1.57 -> r1.58)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/nodes/makefuncs.h.diff?r1=1.57&r2=1.58)
        primnodes.h (r1.127 -> r1.128)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/nodes/primnodes.h.diff?r1=1.127&r2=1.128)