This CL explicitly disables the --freeze-flags-after-init flag for cases
where we modify flags after initialization. This is only tests, fuzzers,
and special options to d8, thus not security relevant.

These should be the last blockers for enabling the flag globally.

R=cbruni@chromium.org

Bug: v8:12887
Change-Id: I1d8a03dcc20e524d30c967f6fe15f6401de77612
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3706619Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81179}