evaluate() bypassed CSP for unsafe-eval by default. This is a useful
option for debugging clients, but is not always what we want.

e.g. in the devtools console we want to match the page's CSP settings
to make debugging CSP issues on the page easier.

Add a toggle that keeps the current behavior by default.

Bug: chromium:1084558
Change-Id: Ia01142d5be00f8ef5f65e5eeba17549efc6f9120
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2250245
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Reviewed-by: Simon Zünd <szuend@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68432}