Revert of Add V8.Execute histogram to measure time spent executing JS code. (patchset #1 id:1 of https://codereview.chromium.org/1974003002/ )

Reason for revert:
Blocks roll https://codereview.chromium.org/1972303002/

Repro:
- build chromium with this CL
- out/Default/content_browsertests --gtest_filter=AccessibilityHitTestingBrowserTest.HitTestingInIframes

Original issue's description:
> Add V8.Execute histogram to measure time spent executing JS code.
>
> Adds a V8.Execute histogram to measure the amount of time spent executing
> JS code.
>
> BUG=v8:4865
> LOG=N
>
> Committed: https://crrev.com/e8f5a2723cf54576b84322ac2ee6ef7abc9df056
> Cr-Commit-Position: refs/heads/master@{#36217}

TBR=cbruni@chromium.org,rmcilroy@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:4865

Review-Url: https://codereview.chromium.org/1970193003
Cr-Commit-Position: refs/heads/master@{#36234}