New revision: 2039736177ee11d96a096cdab9c58cc1d78faa43

This modifies roll.py to update namespaces and header guards.
Also I'm removing --reverse, to avoid making this more complicated.

third_party/encoding/encoding{.h,cc} are already up to date,
since I manually propaged them earlier. So this is why this change
is only updating the template.

Change-Id: I5ddb075c9d6dad28b5665348023860683e964841
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1596392Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Commit-Queue: Johannes Henkel <johannes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61253}