zx_clock_get is a deprecated syscall that we're in the process of
removing. This CL replaces one usage with the modern equivalent.

Ref https://fuchsia.dev/fuchsia-src/contribute/governance/rfcs/0008_remove_zx_clock_get_and_adjust

Bug: fuchsia:61736
Change-Id: Ia595409e30b6d96139da50b83ba25f0f06b601c3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2521438
Commit-Queue: Jody Sankey <jsankey@google.com>
Reviewed-by: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71020}