This assertion was always meant to be a best-effort thing to catch obvious
errors, but the cases where the assumptions it makes fail have been growing. I
could remove it entirely, but I'd be happier keeping at least some basic
sanity checks.
This compromise continues allowing any address below the first argument
pointer, and extends the assertion to also allow anything more than 2KiB above
it. We could probably get away with stretching that to at least 4KiB, but 2
seems safer, and likely enough to catch the obvious cases.
Differential Revision: https://phabricator.services.mozilla.com/D3542
--HG--
extra : rebase_source : 9e17aa3d751f75deff67e40d223fda7aaa4f84f0
extra : amend_source : 86ada4dd01584defeaa5dcb093ad9a73b34f0318