Removed all _ast_int and _ast_flt defines

Removed all _ast_int and _ast_flt defines

The defines _ast_int and _ast_flt used to be generated, but were now defined
in ast_common.h. Most of these defines were not used either, only _ast_intmax_t
and _ast_fltmax_t were used to define another define in sfio.h. Instead, we now
directly use the values `long long` and `long double` to set the defines in
sfio.h and we can safely remove the _ast_int and _ast_flt defines.