kMaximalCodeRangeSize can be zero to indicate no limit, which was
misinterpreted by mksnapshot.

Bug: v8:6666
Change-Id: I512412a5ef866c0595654aa78c6761bc00b82c56
Reviewed-on: https://chromium-review.googlesource.com/1140057Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54486}