- Used `Self` instead of `*const Self` where appropriate (orignally proposed in #19770)
- Replaced `@intFromPtr` and `@ptrFromInt` with `@ptrCast`, `@alignCast`, and pointer arithmetic where appropriate
With this, the only remaining instance on pointer-int conversion in hash_map.zig is in `HashMapUnmanaged.removeByPtr`, which easily be able to be eliminated once pointer subtraction is supported.