Accessing static property as non static

[danielchodusov]

Q	A
Bug report?	yes
Feature request?	no
BC Break report?	no
RFC?	no

Steps required to reproduce the problem

Hi! When trying to sending async email with symfony/mailer serialized serialized with jms/serializer I recieve this this exception using jms/serializer 3.2.0

In DefaultAccessorStrategy.php line 86:

  [ErrorException]
  Notice: Accessing static property Egulias\EmailValidator\EmailLexer::$nullToken as non static

Exception trace:
  at /XXX/vendor/jms/serializer/src/Accessor/DefaultAccessorStrategy.php:86
 Egulias\EmailValidator\EmailLexer::JMS\Serializer\Accessor\{closure}() at /XXX/vendor/jms/serializer/src/Accessor/DefaultAccessorStrategy.php:91

It seems it's to be related to: #960