Remove appending to $errors on success/failure.

Logging boolean values offers no real value, and just balloons memory
consumption. While removing this may cause userland problems having it does as
well.

Fixes #3657

lib/Cake/Utility/Validation.php

@@ -815,10 +815,8 @@ class Validation {
  */
 	protected static function _check($check, $regex) {
 		if (is_string($regex) && preg_match($regex, $check)) {
-			self::$errors[] = false;
 			return true;
 		} else {
-			self::$errors[] = true;
 			return false;
 		}
 	}