Tests: Remove WP_Term::$filter property unset() within term tests.

Removes the `unset()` of the `WP_Term::$filter` property within the term tests.

Why?

Prior to the introduction of WP_Term, the term was added to the cache when its filter property was empty. To test the cache, the tests unset this property to trigger `wp_cache_add()` in `get_term()`. [34997] changed that behavior to trigger `wp_cache_add()` when the term was not found after `wp_cache_get()` (i.e. happened in `WP_Term::get_instance()`).

Unsetting the filter property is and was not needed. Prior to `WP_Term`, the condition was an empty value. With `WP_Term`, the filter property is no longer part of the conditional logic for caching.

Follow-up to [34997], [30954], [34035].

See #61890, #61530.

git-svn-id: https://develop.svn.wordpress.org/trunk@58919 602fd350-edb4-49c9-b593-d223f7449a82

tests/phpunit/tests/term/cache.php

@@ -116,9 +116,6 @@ public function test_get_term_should_update_term_cache_when_passed_an_object() {
 
 		$num_queries = get_num_queries();
 
-		// get_term() will only be update the cache if the 'filter' prop is unset.
-		unset( $term_object->filter );
-
 		$term_object_2 = get_term( $term_object, 'wptests_tax' );
 
 		// No new queries should have fired.

tests/phpunit/tests/term/getTerm.php

@@ -98,7 +98,6 @@ public function test_passing_term_object_should_skip_database_query_when_filter_
 
 		$num_queries = get_num_queries();
 
-		unset( $term->filter );
 		$term_a = get_term( $term, 'wptests_tax' );
 
 		$this->assertSame( $num_queries, get_num_queries() );