Reland "[vm] Fix V8 snapshot profile handling of the dispatch table."

This is a reland of 5909fd111d52e459b4c1885c5805849336df0f71

Does a large refactoring on the V8 snapshot profile writer
to clean things up, add more debugging support, and to fix
the problems that surfaced during the original landing.

Other changes:

Changes Serializer::CreateArtificialNodeIfNeeded() to create
artificial nodes for Code objects and immutable arrays.

Fixes CodeSerializationCluster::Trace() to only push needed parts of
discarded code objects, instead of tracing them like full code objects.

Adds test cases to v8_snapshot_profile_writer_test that exercise
the following situations (both separately and together):

* Non-symbolic stack traces are enabled and code and function objects
  are dropped when not needed at runtime.

* Creation of the dispatch table is disabled.

TEST=vm/dart{,_2}/v8_snapshot_profile_writer_test

Original change's description:
> [vm] Fix V8 snapshot profile handling of the dispatch table.
>
> Fixes https://github.com/dart-lang/sdk/issues/45702.
>
> TEST=Tests listed in the issue above.
>
> Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-linux-debug-x64-try
> Change-Id: Ibf5e3ccf3828c01f9dda47de360314dabe8cb8a9
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/195272
> Reviewed-by: Daco Harkes <dacoharkes@google.com>
> Commit-Queue: Tess Strickland <sstrickl@google.com>

Change-Id: I8e7030267fe190079a8f68d00fe20bf7170e5719
Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-linux-product-x64-try,vm-kernel-precomp-mac-release-simarm64-try,vm-kernel-precomp-linux-debug-x64c-try,vm-kernel-precomp-obfuscate-linux-release-x64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/195513
Reviewed-by: Daco Harkes <dacoharkes@google.com>
Commit-Queue: Tess Strickland <sstrickl@google.com>
19 files changed
tree: 7ab01064de70e65f81bff26c09f679ec645f6755
  1. .dart_tool/
  2. .github/
  3. benchmarks/
  4. build/
  5. client/
  6. docs/
  7. pkg/
  8. runtime/
  9. samples/
  10. samples-dev/
  11. samples_2/
  12. sdk/
  13. tests/
  14. third_party/
  15. tools/
  16. utils/
  17. .clang-format
  18. .gitattributes
  19. .gitconfig
  20. .gitignore
  21. .gn
  22. .mailmap
  23. .packages
  24. .style.yapf
  25. .vpython
  26. AUTHORS
  27. BUILD.gn
  28. CHANGELOG.md
  29. codereview.settings
  30. CONTRIBUTING.md
  31. DEPS
  32. LICENSE
  33. PATENT_GRANT
  34. PRESUBMIT.py
  35. README.dart-sdk
  36. README.md
  37. sdk_args.gni
  38. WATCHLISTS
README.md

Dart

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