Change the initial value of breakType to undefined
Store break type into bits
Change the algorithm

Bug: v8:6891
Change-Id: Id2cc1e90c28d92364318928fc8a377f172ebb339
Reviewed-on: https://chromium-review.googlesource.com/c/1374996Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Commit-Queue: Frank Tang <ftang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58298}