Math.random, while technically not having any effects which modify the
surrounding JS state, does observably change between a no-side-effects
evaluation and an actual evaluation, and can cause confusion.

Change-Id: I4a41ac6fd3153a14245d5940fe52ada43ca05e0b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2207805Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Gus Caplan <me@gus.host>
Cr-Commit-Position: refs/heads/master@{#67927}