[5.0] Fix issue #2330 by limiting the vector size that can be reserve'd

[greg7mdp]

Resolves #2330.

The deserialization of arrays involves reading a size, and then the array elements which are emplace'd back into a std::vector. For normal vectors, since we know the size in advance, it is beneficial to call std::vector::reserve() to prevent quadratic reallocations of the vector's buffer as the values are read. Still, limit the size that can be reserved to 1024 fc::variant values, or 16KB since sizeof(fc::variant) == 16).

[ericpassmore]

Note:start
category: Other
component: Internal
summary: Improve deserialization by limiting vector size that can be reserved, prevent erroring out for large data structures.
Note:end