When lowering JSToLength, we cannot just smash arbitrary bounds on the
Select nodes, as that will confuse the representation selection later.
Instead properly rename the input using NumberMax and NumberMin.

R=jarin@chromium.org
BUG=chromium:657478

Review-Url: https://codereview.chromium.org/2440333002
Cr-Commit-Position: refs/heads/master@{#40519}