Reverts bf642204b373e01314ecfb0c50a643dc4b05746f and uses a different
workaround, suggested by @LemonBoy.
There is either a compiler bug or a design flaw somewhere around here.
It does not have to block this branch, but I need to understand exactly
what's going on here and make it so that nobody ever has to run into
this problem again.
Also known as "Struct-Of-Arrays" or "SOA". The purpose of this data
structure is to provide a similar API to ArrayList but instead of
the element type being a struct, the fields of the struct are in N
different arrays, all with the same length and capacity.
Having this abstraction means we can put them in the same allocation,
avoiding overhead with the allocator. It also saves a tiny bit of
overhead from the redundant capacity and length fields, since each
struct element shares the same value.
This is an alternate implementation to #7854.
