The tail call implementation is hidden behind the --harmony-tailcalls
flag, which is off-by-default (and has been unstaged since February).
It is known to be broken in a variety of cases, including clusterfuzz
security issues (see sample Chromium issues below). To avoid letting
the implementation bitrot further on trunk, this patch removes it.

Bug: v8:4698, chromium:636914, chromium:724746
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng;master.tryserver.v8:v8_linux_noi18n_rel_ng
Change-Id: I9cb547101456a582374fdf7b1a3f044a9ef33e5c
Reviewed-on: https://chromium-review.googlesource.com/569069
Commit-Queue: Adam Klein <adamk@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46651}

This introduces a bunch of new tests that test various aspects of
accessor inlining in TurboFan (without the actual inlining), and does
the appropriate fixes to the AstGraphBuilder. The actual inlining CL
will land separately (so we don't need to revert the tests and fixes
if the accessor CL has to be reverted).

R=jarin@chromium.org

Review-Url: https://codereview.chromium.org/2197913002
Cr-Commit-Position: refs/heads/master@{#38191}

This is necessary to ensure that "Called non callable" exception will get a proper message and stack trace even for calls at tail position.

BUG=chromium:595615, v8:4698
LOG=N

Review URL: https://codereview.chromium.org/1818003002

Cr-Commit-Position: refs/heads/master@{#34962}

BUG=chromium:593697,v8:4698
LOG=N

Review URL: https://codereview.chromium.org/1781303002

Cr-Commit-Position: refs/heads/master@{#34716}

Parallelize test/mjsunit/es6/tail-call-megatest.js in order to avoid timeouts on slow architectures.

Review URL: https://codereview.chromium.org/1778663004

Cr-Commit-Position: refs/heads/master@{#34622}