Change MockHandler to return null instead of false to be similar to other CacheHandlers.

Update Throttler to check for null instead of false when looking for existing bucket.

Author: Mohammed Karim

system/Throttle/Throttler.php

@@ -138,7 +138,7 @@ public function check(string $key, int $capacity, int $seconds, int $cost = 1):
 		$tokenName = $this->prefix . $key;
 
 		// Check to see if the bucket has even been created yet.
-		if (($tokens = $this->cache->get($tokenName)) === false)
+		if (($tokens = $this->cache->get($tokenName)) === null)
 		{
 			// If it hasn't been created, then we'll set it to the maximum
 			// capacity - 1, and save it to the cache.

tests/_support/Cache/Handlers/MockHandler.php

@@ -43,7 +43,7 @@ public function get(string $key)
 
 		return array_key_exists($key, $this->cache)
 			? $this->cache[$key]
-			: false;
+			: null;
 	}
 
 	//--------------------------------------------------------------------