This reverts commit 73dd9b55.

Reason for revert: Broke telemetry layout tests - https://ci.chromium.org/p/chromium/builders/luci.chromium.try/win7-rel/9936 as can be seen in this roll - https://chromium-review.googlesource.com/c/chromium/src/+/1454259

Original change's description:
> [utf8] Rewrite NewStringFromUtf8 using Utf8::ValueOfIncremental
> 
> This is 3-4x faster than using the Utf8Decoder. This matters for proper
> parse-time measurements using d8.
> 
> Change-Id: I9870e9fbe400ec022a6eeb20491c80a2a32f8519
> Reviewed-on: https://chromium-review.googlesource.com/c/1451827
> Commit-Queue: Toon Verwaest <verwaest@chromium.org>
> Reviewed-by: Leszek Swirski <leszeks@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#59347}

TBR=ulan@chromium.org,leszeks@chromium.org,verwaest@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Change-Id: I3f8faebb61c19a41ee496a571228f53c0d5fc8dd
Reviewed-on: https://chromium-review.googlesource.com/c/1454495Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59378}