The name of some sniffs changed in the most recent PHPCompatiblity version. This commit update all instances where those names are used in WooCommerce codebase.
WC_Geolite_Integration::get_country_iso() sometimes returns null instead of an array, so this commit adds a check to account for that possibility before using the returned value. Doing this to prevent the following undefined index notice:
PHP Notice: Undefined index: country in wp-content/plugins/woocommerce/includes/class-wc-geolite-integration.php on line 60
Fixes#20594
Christopher Allford
Rodrigo Primo
Claudio Sanches