Hash dance: Improve readability of FRE tests

This CL is following the style guidelines by adding a comment
to each function arguments to make it non ambiguous.

Bug: 1242309
Change-Id: I73912b834d94e02aeccf7a42ffbbb10e15e2a27c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3122598


Reviewed-by: Maksim Ivanov <emaxx@chromium.org>
Commit-Queue: Amr Aboelkher <amraboelkher@chromium.org>
Cr-Commit-Position: refs/heads/main@{#915925}