We were using 'strtoll' which returns a signed integer, we should have used
'strtoull' instead.

Change-Id: Ie2e48ecc1fa58cff4b61fcea30087608769a80bb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1893333Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Pierre Langlois <pierre.langlois@arm.com>
Cr-Commit-Position: refs/heads/master@{#64765}