Remove old rb_scan_args() warning from 2.7

Author: eregon

lib/cext/ABI_check.txt

@@ -1 +1 @@
-3
+4

lib/cext/include/truffleruby/truffleruby.h

@@ -278,7 +278,6 @@ static inline int rb_tr_scan_args_kw_int(int kw_flag, int argc, VALUE *argv, str
         if (parse_data.rest || argc <= n_mand + n_opt) {
           parse_data.kwargs = false;
           erased_kwargs = true;
-          rb_warn("The last argument is nil, treating as empty keywords");
         }
       }
       else {

spec/tags/optional/capi/util_tags.txt

@@ -2,4 +2,3 @@ fails:C-API Util function rb_scan_args rejects the use of nil as a hash
 fails:C-API Util function rb_scan_args does not reject non-symbol keys in keyword arguments
 fails:C-API Util function rb_scan_args does not reject non-symbol keys in keyword arguments with required argument
 fails:C-API Util function rb_scan_args considers keyword arguments with non-symbol keys as keywords when using splat and post arguments
-fails:C-API Util function rb_scan_args assigns optional arguments with no hash argument given and rejects the use of optional nil argument as a hash