pgsql: Revisit AlterTableCreateToastTable's API once again, hoping to

Log Message:
-----------
Revisit AlterTableCreateToastTable's API once again, hoping to make it what
pg_migrator actually needs and not just a partial solution. We have to be
able to specify the OID that the new toast table should be created with.

Modified Files:
--------------
pgsql/src/backend/catalog:
toasting.c (r1.16 -> r1.17)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/catalog/toasting.c?r1=1.16&r2=1.17)
pgsql/src/backend/commands:
cluster.c (r1.185 -> r1.186)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/cluster.c?r1=1.185&r2=1.186)
tablecmds.c (r1.286 -> r1.287)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/tablecmds.c?r1=1.286&r2=1.287)
pgsql/src/backend/executor:
execMain.c (r1.325 -> r1.326)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/executor/execMain.c?r1=1.325&r2=1.326)
pgsql/src/backend/tcop:
utility.c (r1.308 -> r1.309)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/tcop/utility.c?r1=1.308&r2=1.309)
pgsql/src/include/catalog:
toasting.h (r1.7 -> r1.8)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/toasting.h?r1=1.7&r2=1.8)