d8 treats files with the .mjs extension as modules instead of
classic scripts. Thus, the `// MODULE` pragma and its corresponding
logic in test runners can be removed in favor of explicitly adding
the extension.

Bug: v8:7950, v8:9395, v8:9406
Also-By: tmrts@chromium.org
Change-Id: Ic74328dc5c5f176bb4bdf6d74bdd4d3966279ba5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1675958
Commit-Queue: Mathias Bynens <mathias@chromium.org>
Reviewed-by: Tamer Tas <tmrts@chromium.org>
Auto-Submit: Mathias Bynens <mathias@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62421}

Bug: v8:8801, v8:8394
Change-Id: I6bb46ecafe1bd94adbf0409f13c9b2e558da0823
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1594558
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Mythri Alle <mythria@chromium.org>
Auto-Submit: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Mythri Alle <mythria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61200}

This removes the --turbo flag and solely relies on the filter pattern
provided via --turbo-filter when deciding whether to use TurboFan. Note
that disabling optimization wholesale can still be done with --no-opt,
which should be used in favor of --no-turbo everywhere.

Also note that this contains semantic changes to the TurboFan activation
criteria. We respect the filter pattern more stringently and no longer
activate TurboFan just because the source contains patterns forcing use
of Ignition via {AstNumberingVisitor::DisableFullCodegenAndCrankshaft}.

R=rmcilroy@chromium.org
BUG=v8:6408

Change-Id: I0c855f6a62350eb62283a3431c8cc1baa750950e
Reviewed-on: https://chromium-review.googlesource.com/528121Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46167}

This is sound because the slot never changes, and it enables optimization by
JSContextSpecialization.

R=mstarzinger@chromium.org
BUG=

Review-Url: https://codereview.chromium.org/2662093004
Cr-Commit-Position: refs/heads/master@{#42848}