Change heap_modifytuple() to require a TupleDesc rather than a

src/backend/access/common/heaptuple.c

src/backend/catalog/aclchk.c

src/backend/catalog/pg_operator.c

src/backend/catalog/pg_proc.c

src/backend/catalog/pg_type.c

src/backend/commands/analyze.c

src/backend/commands/async.c

src/backend/commands/comment.c

src/backend/commands/dbcommands.c

src/backend/commands/functioncmds.c

src/backend/commands/schemacmds.c

src/backend/commands/tablecmds.c

src/backend/commands/tablespace.c

src/backend/commands/typecmds.c

src/backend/commands/user.c

src/backend/rewrite/rewriteDefine.c

src/backend/storage/large_object/inv_api.c

src/include/access/heapam.h