R1:7aab7e80af28

Provide default values for table view properties which are `count`ed

Summary:
PHP 7.2 has changed the behavior of `count`, you must provide an array or `Countable` as a parameter, otherwise a warning is generated. These two class members are counted during rendering, and are commonly left as null properties.

https://wiki.php.net/rfc/counting_non_countables

Test Plan: Browsed around my install and stopped seeing `count(): Parameter must be an array or an object that implements Countable at…