[macOS,Windows] Use static casts where possible

[cbracken]

Fixes a few instances where we were using reinterpret_cast and reinterpret_pointer_cast but could have been using static_cast since the types being cast between are related types in the same hierarchy.

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[dkwingsmt]

It works as long as the compiler agrees, right?

[cbracken]

Yeah the various casts are compile-time features (except dynamic_cast which requires RTTI enabled). The real question is whether Windows is happy with this; the patch was written on a Mac, so I haven't tested on my Windows machine, but CI will tell us.