Remove CXT_printf/CXT1_printf macros. If anyone had found them to be of

any use in the past many years, we'd have made some effort to include
them in all executor node types; but in fact they were only in
nodeAppend.c and nodeIndexscan.c, up until I copied nodeIndexscan.c's
occurrence into the new bitmap node types.  Remove some other unused
macros in execdebug.h, too.  Some day the whole header probably ought to
go away in favor of better-designed facilities.