testCommerceProductReferenceReferenceProducts doesn't properly send arguments to commerce_product_match_products

Code

$field_products = commerce_product_match_products($this->field_name, NULL, $new_product->sku, 'equals');

Expected argument value for field is to be a field config array.

Discovered while working on my Travis integrations (https://travis-ci.org/mglaman/commerce-d7-travis/jobs/71593698).