Bug 1799057 - Don't allow allocations sizes larger than isize::MAX in vec_try_extend. r=kinetik, a=RyanVM

On ESR, we have a version of fallible_collections that doesn't have the
rust_1_57 feature, and newer versions that do also pull a new version
of hashbrown, which is an heavy weight change (and would create a
duplicate of hashbrown).

Instead, backport https://github.com/vcombey/fallible_collections/pull/31/commits/f26cad643c852d6b31f0287a517a88d6a0c5b6ac

Differential Revision: https://phabricator.services.mozilla.com/D161236