Both stability and performance looks good on Linux and ChromeOS, which
is the only operation systems that currently support PKU.

Hence enable the feature by default before launching via finch.

R=ahaas@chromium.org

Bug: v8:11974, chromium:1204982
Change-Id: I2c1e7e7bb70ba73218d4db630219870b198ba6e6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3461934Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79103}