Goal is to include coverage of builtin functions into coverage
bitmap send to Fuzzilli fuzzer. In order to do this, after each
REPRL loop, coverage data of bitmaps are retrieved from JS heap
and stored into coverage bitmap. Additionally, there is an option,
to print out statistics about how many of edges from builtin
functions were turned on by the program inputted into REPRL loop.

This commit introduces two flags:
--no-fuzzilli-enable-builtins-coverage - when enable-builtins-coverage
 turned of, builtins coverage will not be exported to fuzzilli

--fuzzilli-coverage-statistics - when turned on, d8 prints
 statistics into covlog.txt file after each loop




Change-Id: I8f9cf8dc693b952467b108c6d6bc00134125bc5f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2263154
Commit-Queue: Peter Ralbovsky <ralbovsky@google.com>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68733}

Fuzzilli is open source fuzzer by Samuel Groß (saelo@google.com)
that can be used to find bugs in v8 javascript engine. As we want
to automate fuzzing for current versions of v8, we want to merge
fuzzilli toolkit into v8 code, so that fuzzer can automatically
update to the newest version.
So far Fuzzilli has been maintained at
https://github.com/googleprojectzero/fuzzilli .


Bug tracker Id: https://bugs.chromium.org/p/v8/issues/detail?id=10571

Change-Id: I83ddc7e8bb31664c19e4044395bb9044a1c12031
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2201760Reviewed-by: Tamer Tas <tmrts@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68132}