Eliminate PackedArrayInit in extensions
Summary:
On the continuing quest to eliminate EmptyArray and plain PackedArrays...
Most extension usages of PackedArrayInit / make_packed_array can be converted over to VArrayInit instead. This change is safe other than (possibly) introducing new notices. Here are the exceptions:
1. array_slice doesn't touch string keys in the array. If there may be some, we use a darray.
2. In ext_collections-pair, ToPHPArray must return a plain array (runtime requirement) so we return a MixedArray.
Reviewed By: dneiter
Differential Revision:
D21699243
fbshipit-source-id:
6eb21519a88f81aa6d88f6e1bc029c37b6af0b0f