Add optional second arg to unserialize()

Returns the number of bytes consumed by reference for
streaming unserialization.

Actual unserialization behavior is not modified at all.

The need for this came up while trying to parse SplDoublyLinkedList's
serialization format which uses a non-standard stream of serialized values.
Improved IS_VAR operands fetching
Recover NEWS

Apperently wrongly merged in revision 488933792a8
Added missing ZE/OPcache related entries
other fix for #64214, unmodified file may not have old fp set, causing other possible crashes
entry for #64214
Merge branch 'PHP-5.3' into PHP-5.4

* PHP-5.3:
  entry for #64214
  other fix for #64214, unmodified file may not have old fp set, causing other possible crashes
Merge branch 'PHP-5.4' of git.php.net:php-src into PHP-5.4
Merge branch 'PHP-5.4' into PHP-5.5

* PHP-5.4:
  entry for #64214
  other fix for #64214, unmodified file may not have old fp set, causing other possible crashes
Merge branch 'PHP-5.5'

* PHP-5.5:
  entry for #64214
  other fix for #64214, unmodified file may not have old fp set, causing other possible crashes