* [C++] Add a failing unit test for #7516 (Rare bad buffer content alignment if sizeof(T) != alignof(T))
* [C++] Fix final buffer alignment when using an array of structs
* A struct can have an arbitrary size and therefore sizeof(struct) == alignof(struct)
does not hold anymore as for value primitives.
* This patch fixes this by introducing alignment parameters to various
CreateVector*/StartVector calls.
* Closes#7516
72aa85a759