php 8.1 compatibility fixes

[falkenhawk]

• fix deprecation notices for Serializable interface Deprecated: Test implements the Serializable interface, which is deprecated. Implement __serialize() and __unserialize() instead (or in addition, if support for old PHP versions is necessary) https://php.watch/versions/8.1/serializable-deprecated

• [zend-amf] fix for php 8.1+ keep the order of properties when they are being serialized same as PHP <8.1

  In PHP 8.1, the order of properties is the same as in the class definition, but properties from parent class always go after properties from the current class. From PHP upgrade notes: https://github.com/php/php-src/blob/578b67da49af51b2f796a48782e51ceb62860943/UPGRADING#L334-L341

  Copied the correlationId property definition from Zend_Amf_Value_Messaging_AsyncMessage to parent Zend_Amf_Value_Messaging_AbstractMessage. correlationId prop is expected to be at the beginning of serialized messages, otherwise it breaks Zend_Amf_ResponseTest cases for php 8.1+.

  This was causing 14 failures in Zend_Amf test suite due to serialized binary data was different than expected, due to changed order of properties of serialized objects.

• [zend-server] fix issue with Zend_Server_Reflection_Method

  Method name was not set in constructor, but it was being read in tests (there is no property defined for it, but __set magic method is defined in the base class) resulting in substr(): Passing null to parameter https://github.com/zf1s/zf1/pull/1 ($string) of type string is deprecated and similar errors in various places

• fixing errors and warnings for php 8.1

• includes #151 and #156

[falkenhawk]

236 errors, 9 failures to go... 😵‍💫 (starting from 1141 errors and 33 failures after #147)

[falkenhawk]

only 6 errors left. all in zend-db

[falkenhawk]

@glensc would you like to review this PR?