The motivation for this CL were the expensive UnhandledIsSorted() checks,
which increase mksnapshot time (v8:7895).
In addition, it is a cleanup and removes a potential for quadratic
performance.

Change-Id: I33e734e4e20183768dbf8222adcbb3abc1f1a6bf
Reviewed-on: https://chromium-review.googlesource.com/1116960
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Stephan Herhut <herhut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54063}