Fix building debase gem's native extension

It fails with the following error:
```
... .rbenv/versions/truffleruby-23.0.0-preview1/lib/gems/gems/debase-ruby_core_source-0.10.18/lib/debase/ruby_core_source/ruby-3.1.0-p0/internal/array.h:106:1: error: static declaration of 'RARRAY_AREF' follows non-static declaration
RARRAY_AREF(VALUE ary, long i)
^
... .rbenv/versions/truffleruby-23.0.0-preview1/lib/cext/include/ruby/internal/core/rarray.h:263:7: note: previous declaration is here
VALUE RARRAY_AREF(VALUE array, long index);
      ^
```

Author: andrykonchin

lib/cext/ABI_check.txt

@@ -1 +1 @@
-2
+3

lib/cext/include/ruby/internal/core/rarray.h

@@ -279,7 +279,7 @@ long rb_array_len(VALUE a);
 int RARRAY_LENINT(VALUE ary);
 VALUE *RARRAY_PTR_IMPL(VALUE array);
 void rb_ary_store(VALUE, long, VALUE);
-VALUE RARRAY_AREF(VALUE array, long index);
+VALUE rb_tr_rarray_aref(VALUE array, long index);
 #endif
 RBIMPL_SYMBOL_EXPORT_END()
 
@@ -611,7 +611,7 @@ RARRAY_ASET(VALUE ary, long i, VALUE v)
  * transition path, but currently no way is found to do so.
  */
 #ifdef TRUFFLERUBY
-#define RARRAY_AREF RARRAY_AREF
+#define RARRAY_AREF rb_tr_rarray_aref
 #else
 #define RARRAY_AREF(a, i) RARRAY_CONST_PTR_TRANSIENT(a)[i]
 #endif

src/main/c/cext/array.c

@@ -20,7 +20,7 @@ int RARRAY_LENINT(VALUE array) {
   return polyglot_get_array_size(rb_tr_unwrap(array));
 }
 
-VALUE RARRAY_AREF(VALUE array, long index) {
+VALUE rb_tr_rarray_aref(VALUE array, long index) {
   return rb_tr_wrap(polyglot_get_array_element(rb_tr_unwrap(array), (int) index));
 }