[Benchmarking] Gtest process provide non-unicode executable name.

Speculative fix. See bug for details.

Bug: 1039019
Change-Id: I15ee33cfba36b1896b089147fd8fa6f6cd9e2459
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1986969
Commit-Queue: Caleb Rouleau <crouleau@chromium.org>
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Auto-Submit: Caleb Rouleau <crouleau@chromium.org>
Reviewed-by: Brian Sheedy <bsheedy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#728353}