Using associative property of addition: (x + A) + B => x + (A + B).
Note: A and B need to have the same sign and we need to check that
(x + A) isn't used anywhere else.

20% perf improvement of the following function.

function f(n) {
  var c = 0;
  for (var i = 0; i < n; i++) {
    c = c + 2 + 3;
  }
  return c;
}
for n = 10_000_000.

Before: 7.31s.
After: 6.05s.

Bug: v8:10305
Change-Id: If45d1cad6128a9a25cb9f43a4828ae28d594a84b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2365221
Commit-Queue: Z Nguyen-Huu <duongn@microsoft.com>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70064}