Compiler: Fixed updating of PROGRAM_{NEEDS,USES}_PARENT. low_inherit() may get called with a parent offset of 24 (OBJECT_PARENT + 42) or 25 (INHERIT_PARENT + 42) when called from decode_value(). Make sure we don't start zapping flags in random programs on the compiler stack when this happens. Fixes [LysLysKOM 20258894] and [LysLysKOM 20273476]/[Pike 13584].