As of crrev.com/2760213003, the CheckBounds operator passes a truncation
that identfies zero and minus zero. However that was not reflected in
the typing rule, and as such the type of CheckBounds(-0,length) was
always Type::None. That confused the typed alias analysis in the
LoadElimination and led to ignoring StoreElement nodes.

BUG=chromium:708050
R=jarin@chromium.org

Review-Url: https://codereview.chromium.org/2812013006
Cr-Commit-Position: refs/heads/master@{#44598}