Microbenchmarks show a 4x improvement on the fast path and 2.5x improvement on
the slow path when compared to the CPP builtin implementation.

Compared to the old JS implementation, the fast path is 20% faster and the slow
path 35% slower.

BUG=v8:5339,v8:5562

Review-Url: https://codereview.chromium.org/2527963002
Cr-Commit-Position: refs/heads/master@{#41338}