Speed up deepclone_from_array()

[nicolas-grekas]

Ideas from symfony/polyfill#716, plus the ones profiling showed.

On the 57 cached payloads of https://github.com/nicolas-grekas/symfony-showcase (Doctrine metadata, serializer, validator, property info and object mapper), deepclone_from_array() needs 14% fewer instructions. On a graph of 1600 objects, it needs 18% fewer.

• Typed properties are written right after checking their type, instead of going through zend_std_write_property(), which looks them up again. This applies when the slot contains no reference, no __set() applies and a readonly property isn't initialized yet. The type is checked like before, in coercive mode.
• Object ids, the most common marker, are resolved inline. A property of the stdClass scope is looked up once per class instead of once per object.
• Without allow_named_closures, the payload is scanned for closures once instead of twice. The scans skip scalar markers.

The results are the same before and after on 11,000 fuzzed payloads.