This has two parts:
- in redundancy elimination, if we see addition with left hand side that
  was bounds-checked, we reconnect the lhs to the bounds check if it has better
  type.
- in representation inference, eliminate overflow checks if the input types
  guarantee no overflow.

Review-Url: https://codereview.chromium.org/2527083002
Cr-Commit-Position: refs/heads/master@{#41260}