Reland "[fuchsia][time] Use C11 timespec APIs for UTC time"
Reland "[fuchsia][time] Use C11 timespec APIs for UTC time"

This is a reland of 0e1d32f10c1aff19f0900a869944ae02a5dec35a

Original change's description:
> [fuchsia][time] Use C11 timespec APIs for UTC time
> 
> UTC time is being removed from the zircon kernel. Using timespec_get
> ensures that the correct userspace UTC clock handle (supplied to the
> process through proc_args) is used for UTC time queries.
> 
> See https://bugs.fuchsia.dev/p/fuchsia/issues/detail?id=57506
> 
> Change-Id: Id22f0c7c7b0dd785ace4b7aa47e3080addf40e61
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/159589
> Commit-Queue: Zach Anderson <9f8b31e960a68dade71618f1ff6da6e23a1edfc9@google.com>
> Auto-Submit: Adam Lesinski <002a924ff83b8ae9ea343d999f3a9a90c7f1da3f@google.com>
> Reviewed-by: Zach Anderson <9f8b31e960a68dade71618f1ff6da6e23a1edfc9@google.com>

Change-Id: I95acd36978491b468a5dfdafdd0e3319d894938b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/160420
Auto-Submit: Adam Lesinski <002a924ff83b8ae9ea343d999f3a9a90c7f1da3f@google.com>
Reviewed-by: Zach Anderson <9f8b31e960a68dade71618f1ff6da6e23a1edfc9@google.com>
Commit-Queue: Zach Anderson <9f8b31e960a68dade71618f1ff6da6e23a1edfc9@google.com>

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