Fix out-of-array-bounds compiler warning

Since the array length check is using a post-increment operator, the
compiler complains that there's a potential write to one element beyond
the end of the array.  This is not possible currently: the only path to
this function is through pg_get_object_address(), which already verifies
that the input array is no more than two elements in length.  Still, a
bug is a bug.

No idea why my compiler doesn't complain about this ...

Pointed out by Dead Rasheed and Peter Eisentraut

src/backend/catalog/objectaddress.c

@@ -1428,7 +1428,7 @@ get_object_address_opf_member(ObjectType objtype,
 		typenames[i] = strVal(lfirst(cell));
 		typaddr = get_object_address_type(OBJECT_TYPE, cell, missing_ok);
 		typeoids[i] = typaddr.objectId;
-		if (i++ >= 2)
+		if (++i >= 2)
 			break;
 	}