Count the Array#product positions in rb_len_t

An int counter overflows once an array has more than INT_MAX elements. On LP64, product with a block then yielded the element at index 1 after the one at INT_MAX, instead of the one at 2**31.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

array.c

@@ -7822,7 +7822,7 @@ rb_ary_product(int argc, VALUE *argv, VALUE ary)
     volatile VALUE t0 = rb_ary_hidden_new(n);
     volatile VALUE t1 = Qundef;
     VALUE *arrays = RARRAY_PTR(t0); /* The arrays we're computing the product of */
-    int *counters = ALLOCV_N(int, t1, n); /* The current position in each one */
+    rb_len_t *counters = ALLOCV_N(rb_len_t, t1, n); /* The current position in each one */
     VALUE result = Qnil;      /* The array we'll be returning, when no block given */
     rb_len_t i,j;
     rb_len_t resultlen = 1;