Re: Missing update of all_hasnulls in BRIN opclasses

For 0002-fixup-brin-has_nulls-20221022.patch :

+       first_row = (bval->bv_hasnulls && bval->bv_allnulls);
+
+       if (bval->bv_hasnulls && bval->bv_allnulls)

It seems the if condition can be changed to `if (first_row)` which is more readable.

Chhers