We have it readily available at all call-sites. There is no need to
request it via GetIsolate on the function itself.

Change-Id: I4936177c47c8adf9dfeafe1e320f8411ae358a5b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2761200Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73470}