ThreadedArray's std.properties may be a packed array, causing assert failures on 8.2

[dktapps]

If ThreadedArray is populated solely by using []=, the keys will be continuous, causing PHP to allocate the properties table as a packed array.

While this is fine for most cases, PHP 8.2 starts to distinguish between packed and assoc arrays, using separate data structures for each. Notably, ReflectionClass->getProperties() results in an assertion failure on ThreadedArray objects.

[dktapps]

Under normal circumstances, the table would be correctly allocated as an array: https://github.com/php/php-src/blob/50a2de78a8ef5c14c5f6b5167316bd04c1bb5aba/Zend/zend_object_handlers.c#L70

However, since ThreadedArray has no properties, this code doesn't run.