This is a reland of 95aa697b

Original change's description:
> [test][d8] Add d8.log.getAndStop helper
>
> The new helper function allows us to write tests for log parsing
> without the need to first generating a log file. This makes it easier
> to spot errors when the log format changes.
>
> - Add d8 global variable
> - Add file_name accessor to Logger and Log classes
> - Change OS::LogFileOpenMode to w+ / wb+
> - Use separate Log::WriteLogHeader method
> - Remove unused logger_ instance variable from Log
>
> Bug: v8:10644
> Change-Id: Ifc7e35aa4e91b3f01f0847843263946e085944c3
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2387563
> Commit-Queue: Camillo Bruni <cbruni@chromium.org>
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Reviewed-by: Toon Verwaest <verwaest@chromium.org>
> Reviewed-by: Sathya Gunasekaran  <gsathya@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#69715}

Bug: v8:10644

TBR=verwaest@chromium.org

Change-Id: I54741344834d88a376b74e2e3a2047e880a94624
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2396081
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Sathya Gunasekaran  <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69769}